KR20220140277A - Method and apparatus for transmitting and receiving signal in a wireless communication system - Google Patents

Abstract

The present disclosure relates to a communication technique for converging a 5G communication system with IoT technology to support a higher data transfer rate after a 4G system, and a system thereof. The present disclosure can be applied to intelligent services (for example, smart home, smart building, smart city, smart car or connected car, health care, digital education, retail business, security- and safety-related services, etc.) based on 5G communication technology and IoT-related technology. Disclosed in the present disclosure is a method for scheduling a terminal in a mobile communication system to support carrier aggregation.

Description

Method and apparatus for transmitting and receiving signals in a wireless communication system {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING SIGNAL IN A WIRELESS COMMUNICATION SYSTEM

The present disclosure relates to a method and apparatus for transmitting and receiving a signal in a wireless communication system.

Efforts are being made to develop an improved ^5G ( ^5th generation) communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G (4th generation) communication system. For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G Network) communication system or the LTE system after (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, the advanced coding modulation (ACM) methods FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technologies FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Information Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT can be applied to fields such as smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, and advanced medical service through convergence and complex between existing IT technology and various industries. have.

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication) are being implemented by 5G communication technologies such as beamforming, MIMO, and array antenna. . The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

As various services can be provided according to the development of the wireless communication system as described above, a method for smoothly providing these services is required.

Based on the above discussion, the present disclosure provides a method for resolving a scheduling constraint due to a lack of radio resources in a wireless communication system.

A method by a terminal in a wireless communication system according to an aspect of the present disclosure includes: receiving, from a base station, information related to setting of cross-carrier scheduling of a secondary cell (SCell); receiving a physical downlink control channel (PDCCH) by monitoring a search space of the SCell, wherein the PDCCH includes a carrier indicator field; and identifying whether the PDCCH is for the cross-carrier scheduling or for self-scheduling based on the carrier indicator field.

In a wireless communication system according to another aspect of the present disclosure, a method by a base station in a wireless communication system includes: transmitting, to a terminal, information related to setting of cross-carrier scheduling of a secondary cell (SCell); and transmitting, to the terminal, a physical downlink control channel (PDCCH) through the SCell, wherein the carrier indicator field identifies whether the PDCCH is for the cross-carrier scheduling or for self-scheduling. can be used for

In one embodiment, when the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is the same as the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell). and may be set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of the SCell.

In one embodiment, when the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is different from the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell). and may be set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of the SCell.

In one embodiment, when the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of the SCell, and , the PDCCH transmitted through the primary cell (PCell) may not include a carrier indicator field.

In one embodiment, when the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is the same as or different from the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell). It is set to a value, and the PDCCH for the self-scheduling of the SCell may not include a carrier indicator field.

According to an embodiment of the present invention, by defining a method for scheduling a UE in a wireless communication system supporting carrier aggregation (CA), a problem of insufficient cell capacity that may occur in a predetermined cell is solved.

1 is a diagram illustrating a basic structure of a time-frequency resource region of a 5G system.
2 is a diagram illustrating an example of a frame structure of a 5G system.
3 is a diagram illustrating another example of a frame structure of a 5G system.
4 is a diagram illustrating another example of a frame structure of a 5G system.
5 is a diagram illustrating a time domain mapping structure of a synchronization signal and a beam sweeping operation.
6 is a diagram illustrating a random access procedure.
7 is a diagram illustrating a procedure in which a terminal reports UE capability information to a base station.
8 is a diagram illustrating the concept of carrier aggregation (CA).
9 is a diagram illustrating a self carrier scheduling method in a carrier bundle.
10 is a diagram illustrating a cross carrier scheduling method in a carrier bundle.
11A shows an example in which LTE and 5G systems overlap in the same frequency band.
11B shows an example in which LTE and 5G systems partially overlap in the frequency domain.
12 is a diagram illustrating a basic structure of a time-frequency resource region of an LTE system.
13 is a diagram illustrating a method for avoiding collision of LTE and 5G signals in a DSS system.
14 is a diagram illustrating a search space after an initial access of a terminal in a wireless communication system according to an embodiment of the present disclosure.
15 is a diagram illustrating an NR PDCCH search space in a wireless communication system according to an embodiment of the present disclosure.
16 is a diagram illustrating a method for a UE to monitor an NR PDCCH search space in a wireless communication system according to an embodiment of the present disclosure.
17 is a diagram illustrating a method of transmitting an NR PDCCH in a wireless communication system according to an embodiment of the present disclosure.
18 is another diagram illustrating an NR PDCCH transmission method in a wireless communication system according to an embodiment of the present disclosure.
19 is a diagram illustrating a procedure for setting a carrier bundle in a wireless communication system according to an embodiment of the present disclosure.
20 is a diagram illustrating NR PDCCH configuration information according to an embodiment of the present disclosure.
21 is a diagram illustrating an apparatus for transmitting and receiving a terminal in a wireless communication system according to an embodiment of the present disclosure.
22 is a block diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure.
23 is a block diagram illustrating a configuration of a base station according to an embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in the description of the present disclosure, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present disclosure, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

Advantages and features of the present disclosure, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only the present embodiments allow the disclosure of the present disclosure to be complete, and common knowledge in the technical field to which the present disclosure belongs It is provided to fully inform the possessor of the scope of the invention, and the present disclosure is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions. These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory. It is also possible for the instructions stored in the flowchart block(s) to produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s). The computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to create a computer or other programmable data processing equipment. It is also possible that instructions for performing the processing equipment provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in the blocks to occur out of order. For example, two blocks shown one after another may in fact be performed substantially simultaneously, or it is possible that the blocks are sometimes performed in the reverse order according to the corresponding function.

At this time, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and '~ unit' performs certain roles do. However, '-part' is not limited to software or hardware. '~unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card. Also, in an embodiment, '~ part' may include one or more processors.

In the following description of the present disclosure, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

A term for identifying an access node used in the following description, a term referring to a network entity (network entity), a term referring to messages, a term referring to an interface between network objects, and various identification information Reference terms and the like are exemplified for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

In the following description, a physical channel and a signal may be used interchangeably with data or a control signal. For example, a physical downlink shared channel (PDSCH) is a term referring to a physical channel through which data is transmitted, but the PDSCH may also be used to refer to data. That is, in the present disclosure, an expression 'transmitting a physical channel' may be interpreted equivalently to an expression 'transmitting data or a signal through a physical channel'.

Hereinafter, in the present disclosure, higher signaling refers to a signal transmission method in which a base station is transmitted to a terminal using a downlink data channel of a physical layer, or from a terminal to a base station using an uplink data channel of a physical layer. Upper signaling may be understood as radio resource control (RRC) signaling or media access control (MAC) control element (CE).

For convenience of description, the present disclosure uses terms and names defined in the 3GPP NR (New Radio: 5th Generation Mobile Communication Standard) standard. However, the present disclosure is not limited by the terms and names, and may be equally applied to systems conforming to other standards. Also, the term terminal may refer to mobile phones, smart phones, IoT devices, sensors, as well as other wireless communication devices.

Hereinafter, the base station is a subject that performs resource allocation of the terminal, and may be at least one of gNode B, gNB, eNode B, eNB, Node B, BS (Base Station), radio access unit, base station controller, or a node on the network. . The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Of course, it is not limited to the above example.

5G, the next-generation communication system after LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)) and LTE-A (LTE-Advanced or E-UTRA Evolution) to handle the recently explosively increasing mobile data traffic (5 ^th Generation) system or New Radio access technology (NR) initial standard has been completed. Whereas the existing mobile communication system focused on normal voice/data communication, the 5G system provides eMBB (enhanced Mobile BroadBand) service for improving the existing voice/data communication, high reliability/ultra-low latency (Ultra-Reliable and Low). It aims to satisfy various services and requirements, such as Latency Communication (URLLC) service and massive MTC (Machine Type Communication) service that supports mass communication of objects.

While the existing LTE and LTE-A system transmission bandwidth per single carrier is limited to a maximum of 20 MHz, the 5G system aims to provide ultra-high-speed data services up to several Gbps by utilizing a much wider ultra-wide bandwidth. Accordingly, the 5G system considers the ultra-high frequency band from several GHz up to 100 GHz, which is relatively easy to secure, as a candidate frequency. In addition, it is possible to secure a wide bandwidth frequency for the 5G system through frequency relocation or allocation among frequency bands included in several GHz to several hundred MHz used in the existing mobile communication system.

The radio wave in the ultra-high frequency band has a wavelength of several millimeters and is sometimes referred to as a millimeter wave (mmWave). However, in the very high frequency band, the pathloss of radio waves increases in proportion to the frequency band, so that the coverage of the mobile communication system becomes small.

In order to overcome the drawback of reducing the coverage in the ultra-high frequency band, a beamforming technology is applied to increase the reach of radio waves by concentrating the radiant energy of radio waves to a predetermined target point using a plurality of antennas. That is, in the signal to which the beamforming technology is applied, the beam width of the signal is relatively narrowed, and the radiation energy is concentrated in the narrowed beam width to increase the radio wave arrival distance. The beamforming technique can be applied to a transmitter and a receiver, respectively. In addition to the effect of increasing the coverage, the beamforming technique has an effect of reducing interference in a region other than the beamforming direction. In order for the beamforming technology to operate properly, an accurate measurement and feedback method of a transmit/receive beam is required. The beamforming technique may be applied to a control channel or a data channel corresponding to a one-to-one correspondence between a predetermined terminal and a base station. In addition, the base station transmits a common signal to a plurality of terminals in the system, for example, a synchronization signal, a physical broadcast channel (PBCH), a control channel and a data channel for transmitting system information. Also, beamforming technology can be applied to increase coverage. When the beamforming technology is applied to the common signal, the beam sweeping technology, which transmits the signal by changing the beam direction, is additionally applied so that the common signal can be reached to the terminal located at any position in the cell. do.

As another requirement of the 5G system, an ultra-low latency service with a transmission delay of about 1 ms between the transmitting and receiving ends is required. As one method to reduce transmission delay, it is necessary to design a frame structure based on short TTI (Transmission Time Interval) shorter than LTE and LTE-A. The TTI is a basic time unit for performing scheduling, and the TTI of the existing LTE and LTE-A systems is 1 ms corresponding to the length of one subframe. For example, as a short TTI to satisfy the requirement for ultra-low delay service of the 5G system, 0.5ms, 0.25ms, 0.125ms, etc. shorter than the existing LTE and LTE-A systems are possible.

The present disclosure relates to a method and apparatus for transmitting and receiving a terminal in a wireless communication system to which carrier aggregation (CA) is applied.

The present disclosure relates to a cellular wireless communication system, and to a method of transmitting and receiving a control channel and a data channel of a terminal performing a carrier bundling operation.

The present disclosure may provide a method of resolving a scheduling constraint due to a lack of radio resources in a wireless (mobile) communication system.

The present disclosure defines a method of scheduling a UE in a wireless (mobile) communication system supporting carrier aggregation (CA), thereby solving a cell capacity shortage problem that may occur in a given cell.

1 is a diagram illustrating a basic structure of a time-frequency resource region of a 5G system. That is, FIG. 1 is a diagram showing the basic structure of a time-frequency resource region, which is a radio resource region in which data or control channels of a 5G system are transmitted.

(102)개의 심벌이 모여 하나의 슬롯(106)을 구성하고,

개의 슬롯이 모여 하나의 서브프레임 (105)을 구성할 수 있다. 상기 서브프레임의 길이는 1.0ms 이고, 10개의 서브프레임이 모여 10ms 프레임 (114)을 구성할 수 있다. 주파수 영역에서의 최소 전송단위는 서브캐리어(subcarrier)로서, 전체 시스템 전송 대역 (Transmission bandwidth)의 대역폭은 총 N_BW (104)개의 서브캐리어로 구성될 수 있다.Referring to FIG. 1 , in FIG. 1 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain of the 5G system is an OFDM (Orthogonal Frequency Division Multiplexing) symbol,

(102) symbols are gathered to form one slot 106,

Slots may be gathered to configure one subframe 105 . The length of the subframe is 1.0ms, and 10 subframes may be gathered to form a 10ms frame 114 . The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission bandwidth may be composed of a total of N _BW 104 subcarriers.

(110)개의 연속된 서브캐리어로 정의될 수 있다. 5G 시스템에서

= 12 이고, 단말에게 스케줄링되는 RB 개수에 비례하여 데이터 레이트가 증가할 수 있다. A basic unit of a resource in the time-frequency domain is a resource element (RE) 112 and may be represented by an OFDM symbol index and a subcarrier index. Resource Block (RB) in the frequency domain

It can be defined as (110) consecutive subcarriers. in 5G systems

= 12, and the data rate may increase in proportion to the number of RBs scheduled for the UE.

In the 5G system, the base station maps data in units of RBs, and in general, may perform scheduling on RBs constituting one slot for a given terminal. That is, in the 5G system, a basic time unit for scheduling may be a slot, and a basic frequency unit for scheduling may be an RB.

은 심벌간 간섭 방지를 위해 심벌마다 추가되는 순환 프리픽스(Cyclic Prefix, CP)의 길이에 따라 정해지는데, 예를 들어 일반형 CP (Normal CP)가 적용되면

= 14, 확장형 CP (Extended CP)가 적용되면

= 12 일 수 있다. 확장형 CP 는 일반형 CP 보다 전파 전송 거리가 상대적으로 긴 시스템에 적용되어 심벌 간 직교성을 유지할 수 있게 한다. 일반형 CP의 경우, CP 길이와 심벌 길이의 비율이 일정한 값으로 유지됨으로써, CP 로 인한 오버헤드가 서브케리어 간격에 관계 없이 일정하게 유지될 수 있다. 즉, 서브케리어 간격이 작으면 심벌 길이는 길어지고, 이에 따라 CP 길이도 길어질 수 있다. 반대로, 서브케리어 간격이 크면 심벌 길이는 짧아지고, 이에 따라 CP 길이는 줄어들 수 있다. 심벌 길이와 CP 길이는 서브캐리어 간격에 반비례할 수 있다. Number of OFDM symbols

is determined according to the length of a Cyclic Prefix (CP) added to each symbol to prevent inter-symbol interference. For example, when a Normal CP is applied,

= 14, when Extended CP is applied

= 12. The extended CP is applied to a system having a relatively longer radio transmission distance than the general CP, so that orthogonality between symbols can be maintained. In the case of the general type CP, since the ratio of the CP length to the symbol length is maintained at a constant value, the overhead due to the CP may be maintained constant regardless of the subcarrier interval. That is, if the subcarrier interval is small, the symbol length may be increased, and accordingly, the CP length may also be increased. Conversely, if the subcarrier interval is large, the symbol length may be shortened, and accordingly, the CP length may be reduced. The symbol length and the CP length may be inversely proportional to the subcarrier spacing.

In the 5G system, various frame structures can be supported by adjusting the subcarrier interval in order to satisfy various services and requirements. for example,

- From the viewpoint of the operating frequency band, the larger the subcarrier spacing is, the more advantageous the phase noise recovery in the high frequency band is.

- In terms of transmission time, if the subcarrier interval is large, the symbol length in the time domain is shortened, and as a result, the slot length is shortened, which is advantageous to support an ultra-low delay service such as URLLC.

In terms of cell size, since a larger cell can be supported as the CP length is longer, a relatively large cell can be supported as the subcarrier interval is smaller. A cell is a concept indicating an area covered by one base station in mobile communication.

The subcarrier spacing, CP length, etc. are essential information for OFDM transmission/reception, and smooth transmission/reception is possible only when the base station and the terminal recognize them as mutually common values. [Table 1] shows the relationship between subcarrier spacing configuration ( μ ), subcarrier spacing ( Δf ), and CP length supported by the 5G system.

), 한 프레임당 슬롯 개수 (

), 한 서브프레임 당 슬롯 개수 (

)를 나태난다.[Table 2] shows the number of symbols per slot (

), the number of slots per frame (

), the number of slots per subframe (

) appears.

), 한 프레임당 슬롯 개수 (

), 한 서브프레임 당 슬롯 개수 (

)를 나태난다.[Table 3] shows the number of symbols per slot for each subcarrier interval setting ( μ ) in the case of extended CP

), the number of slots per frame (

), the number of slots per subframe (

) appears.

2, 3, and 4 show examples of frame structures in the case of subcarrier spacing settings μ = 0, 1, and 2, respectively, and a general type CP. 2, 3, and 4 illustrate that a subcarrier interval, a CP length, a slot length, etc. are included as essential parameter sets defining a frame structure.

In the initial stage of introduction of the 5G system, at least coexistence or dual mode operation with the existing LTE/LTE-A system is expected. As a result, the existing LTE/LTE-A may provide stable system operation to the terminal, and the 5G system may serve to provide an improved service to the terminal. Therefore, the frame structure of the 5G system needs to include at least the frame structure of LTE/LTE-A or an essential parameter set (subcarrier spacing = 15kHz).

2 is a diagram illustrating an example of a frame structure of a 5G system. That is, FIG. 2 shows a 5G frame structure such as a frame structure of LTE/LTE-A or a set of essential parameters.

)로 RB(Resource Block)가 구성되는 예시를 도시한다. 이 경우, 1 개의 슬롯이 1 개의 서브프레임을 구성하고, 10 개의 서브프레임이 1 개의 프레임을 구성할 수 있다.Referring to FIG. 2, FIG. 2 is a frame structure in which subcarrier spacing is set μ = 0, subcarrier spacing is 15kHz, 14 symbols constitute 1ms slots, and 12 subcarriers (=180kHz =

) shows an example in which an RB (Resource Block) is configured. In this case, one slot may constitute one subframe, and ten subframes may constitute one frame.

3 is a diagram illustrating another example of a frame structure of a 5G system.

)로 RB가 구성되는 예시를 도시한다. 즉, 도 2의 프레임 구조 대비 도 3의 프레임 구조는 서브케리어 간격과 RB 크기는 2배 커지고, 슬롯 길이와 심벌 길이는 2배 작아진 것을 나타낸다. 이 경우, 2 개의 슬롯이 1 개의 서브프레임을 구성하고, 20 개의 서브프레임이 1 개의 프레임을 구성할 수 있다.Referring to FIG. 3, FIG. 3 is a frame structure with a subcarrier interval setting μ = 1, the subcarrier interval is 30 kHz, 14 symbols constitute a 0.5 ms slot, and 12 subcarriers (=360 kHz =

) shows an example in which the RB is configured. That is, compared to the frame structure of FIG. 2 , in the frame structure of FIG. 3 , the subcarrier interval and the RB size are twice as large, and the slot length and the symbol length are twice as small. In this case, two slots may constitute one subframe, and 20 subframes may constitute one frame.

4 is a diagram illustrating another example of a frame structure of a 5G system.

)로 RB가 구성되는 예시를 도시한다. 즉, 상기 도 2의 프레임 구조 대비 도 4의 프레임 구조는 서브케리어 간격과 RB(또는, PRB(Physical Resource Block)) 크기는 4배 커지고, 슬롯 길이와 심벌 길이는 4배 작아진 것을 나타낸다. 이 경우, 4 개의 슬롯이 1 개의 서브프레임을 구성하고, 40 개의 서브프레임이 1 개의 프레임을 구성할 수 있다.Referring to FIG. 4, FIG. 4 is a frame structure with a subcarrier interval setting μ = 2, a subcarrier interval is 60 kHz, 14 symbols constitute a 0.25 ms subframe, and 12 subcarriers (=720 kHz =

) shows an example in which the RB is configured. That is, compared to the frame structure of FIG. 2 , the frame structure of FIG. 4 shows that the subcarrier interval and the RB (or physical resource block (PRB)) size are 4 times larger, and the slot length and the symbol length are 4 times smaller. In this case, 4 slots may constitute one subframe, and 40 subframes may constitute one frame.

That is, if the frame structure described in FIGS. 2 to 4 is generalized, the essential parameter sets, such as subcarrier interval, CP length, slot length, etc., have a relationship of an integer multiple for each frame structure, so that high scalability can be provided. . In addition, a subframe having a fixed length of 1 ms may be defined to indicate a reference time unit independent of the frame structure.

The frame structure illustrated in FIGS. 2 to 4 may be applied to correspond to various scenarios. In view of the cell size, since a larger cell can be supported as the CP length is longer, the frame structure of FIG. 2 can support a cell relatively larger than the frame structure of FIGS. 3 and 4 . From the viewpoint of the operating frequency band, the larger the subcarrier interval is, the more advantageous it is to recover the phase noise in the high frequency band, so that the frame structure of FIG. 4 can support a relatively high operating frequency compared to the frame structure of FIGS. 2 and 3 . From a service point of view, in order to support an ultra-low delay service like URLLC, the shorter the slot length, which is the basic time unit of scheduling, the better. .

Hereinafter, in the description of the present disclosure, an uplink (UL) means a radio link in which a terminal transmits data or control signals to a base station, and a downlink (DL) is a method in which the base station transmits data or control signals to the terminal. It may mean a wireless link.

In the initial access stage when the terminal first accesses the system, the terminal synchronizes downlink time and frequency from a synchronization signal transmitted by the base station through cell search, and performs cell ID (cell ID). ID) can be obtained. In addition, the UE may receive a PBCH (Physical Broadcast Channel) by using the obtained cell ID, and may obtain MIB (Master Information Block), which is essential system information, from the PBCH. Additionally, the terminal may receive system information (SIB) transmitted by the base station to obtain control information related to transmission and reception common to the cell. The cell common transmission/reception related control information may include random access related control information, paging related control information, and/or common control information for various physical channels.

A synchronization signal is a reference signal for cell search, and subcarrier spacing may be applied to suit a channel environment, such as phase noise, for each frequency band. In the case of a data channel or a control channel, in order to support various services as described above, a subcarrier interval may be differently applied according to a service type.

5 is a diagram illustrating a time domain mapping structure of a synchronization signal and a beam sweeping operation.

For the sake of explanation, the following components can be defined

- PSS (Primary Synchronization Signal): A signal that serves as a reference for DL time/frequency synchronization.

- SSS (Secondary Synchronization Signal): It serves as a standard for DL time/frequency synchronization and provides cell ID information. Additionally, it may serve as a reference signal for demodulation of the PBCH.

- PBCH (Physical Broadcast Channel): Provides MIB (Master Information Block) which is essential system information required for transmitting and receiving a data channel and a control channel of a UE. The essential system information is search space related control information indicating radio resource mapping information of a control channel, scheduling control information for a separate data channel for transmitting system information, and/or a frame unit index serving as a timing reference. It may include information such as a System Frame Number (SFN).

- SS/PBCH Block (Synchronization Signal/PBCH Block or SSB): The SS/PBCH block consists of N OFDM symbols and is composed of a combination of PSS, SSS, PBCH, etc. In the case of a system to which beam sweeping technology is applied, the SS/PBCH block is the smallest unit to which beam sweeping is applied. N = 4 in 5G system. The base station can transmit a maximum of L SS/PBCH blocks, and the L SS/PBCH blocks are mapped in a half frame (0.5 ms). In addition, the L SS/PBCH blocks are periodically repeated in units of a predetermined period P. The period P may be notified by the base station to the terminal through signaling. If there is no separate signaling for the period P, the terminal applies a preset default value.

Referring to FIG. 5, FIG. 5 shows that beam sweeping is applied in units of SS/PBCH blocks according to the passage of time. In the example of FIG. 5 , terminal 1 505 receives the SS/PBCH block with a beam radiated in the #d0 503 direction by beamforming applied to the SS/PBCH block #0 at time t1 501 . And UE2 506 receives the SS/PBCH block with a beam radiated in the direction #d4 504 by beamforming applied to SS/PBCH block #4 at time t2 502 . The terminal may obtain an optimal synchronization signal through a beam radiated from the base station in the direction in which the terminal is located. For example, it may be difficult for UE1 505 to obtain time/frequency synchronization and essential system information from an SS/PBCH block through a beam radiated in the #d4 direction away from the position of UE1.

In addition to the initial access procedure, the UE may receive the SS/PBCH block to determine whether radio link quality of the current cell is maintained at a predetermined level or more. In addition, in a procedure in which the UE performs handover from the current cell to the neighboring cell, the UE may receive the SS/PBCH block of the neighboring cell in order to determine the radio link quality of the neighboring cell and obtain time/frequency synchronization of the neighboring cell.

After the terminal acquires MIB and system information from the base station through an initial access procedure, the terminal performs a random access procedure to switch the link with the base station to a connected state (connected state or RRC_CONNECTED state). can be done Upon completion of the random access procedure, the terminal is switched to a connected state, and one-to-one communication is enabled between the base station and the terminal. Hereinafter, a random access procedure will be described in detail with reference to FIG. 6 .

6 is a diagram illustrating a random access procedure.

Referring to FIG. 6 , as a first step 610 of the random access procedure, the terminal transmits a random access preamble to the base station. In the random access procedure, the random access preamble, which is the first message transmitted by the terminal, may be referred to as message 1. The base station can measure the transmission delay value between the terminal and the base station from the random access preamble and align the uplink synchronization. In this case, the UE may arbitrarily select which random access preamble to use in the random access preamble set given by the system information in advance. In addition, the initial transmission power of the random access preamble may be determined according to the pathloss between the base station and the terminal measured by the terminal. In addition, the terminal can transmit the random access preamble by determining the transmission beam direction of the random access preamble from the synchronization signal received from the base station.

In the second step 620 , the base station transmits an uplink transmission timing adjustment command to the terminal from the transmission delay value measured from the random access preamble received in the first step 610 . Also, the base station may transmit an uplink resource and a power control command to be used by the terminal as scheduling information. Control information for an uplink transmission beam of the terminal may be included in the scheduling information.

If the terminal does not receive a random access response (RAR) (or message 2), which is scheduling information for message 3, from the base station within a predetermined time in the second step 620, the first step 610 can proceed again. If the first step 610 is performed again, the terminal increases the random access preamble transmission power by a predetermined step and transmits it (power ramping), thereby increasing the random access preamble reception probability of the base station.

In the third step 630, the terminal transmits uplink data (message 3) including its terminal ID to the base station using the uplink resource allocated in the second step 620 to an uplink data channel (Physicla Uplink Shared Channel, PUSCH). ) through the The transmission timing of the uplink data channel for transmitting Message 3 may follow the timing control command received from the base station in step 620 . In addition, the transmission power of the uplink data channel for transmitting Message 3 may be determined in consideration of the power control command received from the base station in the second step 620 and the power ramping value of the random access preamble. The uplink data channel for transmitting Message 3 may mean the first uplink data signal transmitted by the terminal to the base station after the terminal transmits the random access preamble.

In the fourth step 640, when the base station determines that the terminal has performed random access without colliding with other terminals, data (message 4) including the ID of the terminal that transmitted the uplink data in the third step 630 is transmitted. transmitted to the corresponding terminal. When a signal transmitted by the base station is received from the base station in the fourth step 640 , the terminal may determine that the random access is successful. In addition, the terminal may transmit HARQ-ACK information indicating whether the message 4 is successfully received to the base station through a physical uplink control channel (PUCCH).

If the base station fails to receive the data signal from the terminal because the data transmitted by the terminal in the third step 630 collide with the data of the other terminal, the base station may not transmit any more data to the terminal. Accordingly, if the terminal fails to receive the data transmitted from the base station in the fourth step 640 within a predetermined time, it is determined that the random access procedure has failed and can start over from the first step 610 .

When the random access procedure is successfully completed, the terminal is switched to a connected state, and one-to-one communication between the base station and the terminal can be enabled. The base station may receive UE capability information from the connected terminal and adjust scheduling with reference to the UE capability information of the corresponding terminal. The terminal may inform the base station whether the terminal itself supports a predetermined function, the maximum allowable value of the function supported by the terminal, and the like, through the UE capability information. Accordingly, the UE capability information reported by each terminal to the base station may be a different value for each terminal.

As an example, the UE may report UE capability information including at least a part of the following control information as the UE capability information to the base station.

- Control information related to frequency bands supported by the terminal

- Control information related to the channel bandwidth supported by the terminal

- Control information related to the maximum modulation method supported by the terminal

- Control information related to the maximum number of beams supported by the terminal

- Control information related to the maximum number of layers supported by the terminal

- CSI reporting related control information supported by the UE

- Control information on whether the terminal supports frequency hopping

- When supporting carrier aggregation (CA), bandwidth-related control information

- Control information on whether cross carrier scheduling is supported when carrier bundle is supported

7 is a diagram illustrating a procedure in which a terminal reports UE capability information to a base station.

Referring to FIG. 7 , in step 710 , the base station 702 may transmit a UE capability information request message to the terminal 701 . In response to a request for UE capability information from the base station, the terminal transmits UE capability information to the base station in step 720 .

Hereinafter, a scheduling method in which the base station transmits downlink data to the terminal or instructs the terminal to transmit uplink data will be described.

Downlink control information (DCI) is control information transmitted from a base station to a terminal through downlink, and may include downlink data scheduling information or uplink data scheduling information for a predetermined terminal. In general, the base station can independently channel-code DCI for each terminal, and then transmit it to each terminal through a physical downlink control channel (PDCCH), which is a downlink physical control channel.

Whether the base station is scheduling information for downlink data, scheduling information for uplink data (Uplink grant), or spatial multiplexing using multiple antennas for a terminal to be scheduled , it is possible to apply and operate a predetermined DCI format according to the purpose, such as whether it is DCI for power control.

The base station may transmit downlink data to the terminal through a Physical Downlink Shared Channel (PDSCH), which is a physical channel for downlink data transmission. Scheduling information such as a specific mapping location, modulation scheme, HARQ-related control information, and power control information in the time and frequency domain of the PDSCH is transmitted from the base station to the terminal through the DCI related to the downlink data scheduling information among the DCI transmitted through the PDCCH. can tell you

The UE may transmit uplink data to the base station through a Physical Uplink Shared Channel (PUSCH), which is a physical channel for uplink data transmission. Scheduling information such as a specific mapping position, modulation scheme, HARQ-related control information, and power control information in the time and frequency domain of PUSCH will be notified by the base station to the UE through DCI related to uplink data scheduling information among DCI transmitted through the PDCCH. can

As described above, in order to achieve ultra-high-speed data service up to several Gbps in the 5G system, signal transmission and reception of ultra-wide bandwidths of tens to hundreds of MHz or several GHz may be supported. The ultra-wide bandwidth signal transmission and reception may be supported through a single component carrier (CC) or through a carrier aggregation (CA) technology combining multiple component carriers. In the case of carrier bundling technology, when a mobile operator fails to secure a frequency of sufficient bandwidth to provide a high-speed data service with a single component carrier, each component carrier with a relatively small bandwidth size is combined to increase the total frequency bandwidth and, as a result, It can enable high-speed data service.

8 is a diagram illustrating the concept of carrier aggregation (CA).

8 shows an example of configuring a 5G system by combining three component carriers for each case of uplink and downlink. In the carrier bundle system, each component carrier may be divided into PCell or SCell and operated. A PCell (Primary Cell) (or a first cell) provides a basic radio resource to a UE and may refer to a cell that is a reference for performing operations such as initial access and handover of the UE. The PCell may be configured with a downlink primary frequency (or Primary Component Carrier; PCC) and an uplink primary frequency. The terminal transmits UCI (Uplink Control Information), which is uplink control information including HARQ ACK/NACK that feeds back whether or not there is an error in data received from the base station, or CSI indicating the channel state between the base station and the terminal, to the uplink control channel PUCCH. (Physical Uplink Control Channel) may be transmitted, and PUCCH may be transmitted through a PCell. And, the SCell (Secondary Cell) (or the second cell) is a cell that provides additional radio resources together with the PCell to the UE, and consists of a downlink secondary frequency (or Secondary Component Carrier, SCC) and an uplink secondary frequency or It may be configured as a downlink secondary frequency. The configuration of each component carrier is independent of each other, and the downlink carrier bundle and the uplink carrier bundle can be applied independently of each other. For example, a carrier bundle combining a component carrier of a 100 MHz bandwidth and two component carriers of a 50 MHz bandwidth is applied to the downlink, and only one component carrier of a 100 MHz bandwidth may be used in the uplink (that is, the carrier bundle may not be applied) can). In the present disclosure, unless otherwise stated, a cell and a component carrier may be mixed and used without distinction. Carrier bundle related settings such as which component carriers to combine, how many component carriers to combine, or control information related to the bandwidth of each component carrier may be notified by the base station to the terminal through signaling.

In the carrier bundle system, independent control information and data may be generated and transmitted for each component carrier. Specifically, a method for scheduling a UE in a carrier bundle system may be classified into two types: a self carrier scheduling method and a cross carrier scheduling method. In this disclosure, self carrier scheduling may mean, for example, that a serving cell is scheduled by its own PDCCH, and cross carrier scheduling may mean, for example, that a serving cell is scheduled by the PDCCH of another cell (scheduling cell). could mean to be In this disclosure, self carrier scheduling may be abbreviated as self scheduling.

9 is a diagram illustrating a self carrier scheduling method in a carrier bundle.

Referring to FIG. 9, it is assumed that a 5G system in which two downlink configuration carriers (CC#0 901, CC#1 902) are combined. In the example of FIG. 9 , the base station may transmit a downlink data channel (Physical Data Shared Channel, PDSCH) (eg, 905, 907) to any UE through CC#0 901 and CC#1 902. . At this time, the PDCCH 904 for scheduling the PDSCH 905 of CC#0 901 is transmitted to the UE through CC#0 901, and a PDCCH for scheduling the PDSCH 907 of CC#1 ( 906) may be transmitted to the UE through CC#1 902. As such, a scheduling method in which a data channel and a control channel for scheduling the data channel are transmitted on the same carrier or the same cell may be referred to as self carrier scheduling.

10 is a diagram illustrating a cross carrier scheduling method in a carrier bundle.

Referring to FIG. 10, FIG. 10 exemplifies a system to which carrier bundle is applied to two downlink configuration carriers (CC#0 (1001) and CC#1 (1002)). In FIG. 10 , the base station may transmit a downlink data channel (Physical Data Shared Channel, PDSCH) (eg, 1005, 1007) to an arbitrary terminal through CC#0 1001 and CC#1 1002. At this time, the PDCCH 1004 for scheduling the PDSCH 1005 of CC#0 1001 and the PDCCH 1006 for scheduling the PDSCH 1007 of the CC#1 1002 are both CC#0 1001. may be transmitted to the terminal through That is, in the case of CC#1 1001, a data channel and a control channel for scheduling the data channel may be transmitted on different carriers or different cells. Such a scheduling method may be referred to as cross carrier scheduling.

9 and 10 describe the downlink carrier aggregation technique, the examples of FIGS. 9 and 10 may be similarly applied to the uplink carrier aggregation technique.

Cross-carrier scheduling can obtain the following effects compared to self-carrier scheduling.

One) Control channel offloading: When radio resources for transmitting the control channel are insufficient on a predetermined carrier, the control channel may be transmitted on a separate carrier having relatively sufficient radio resources. For example, in the case of FIG. 10, if the bandwidth of CC#1 is 20 MHz and the bandwidth of CC#0 is 100 MHz, CC#0 is relatively sufficient as a radio resource for control channel transmission.

2) Control channel interference management: Relatively strong interference may occur in a predetermined carrier due to factors of the surrounding environment, frequency characteristics, and the like. Due to the interference, the transmission/reception performance of the control channel may deteriorate. In this case, the control channel transmission/reception performance deterioration may be avoided by transmitting the control channel through a carrier having a relatively low interference effect. On the other hand, since the data channel can be recovered by HARQ (Hybrid Automatic Repeate reQuest) operation even if a transmission/reception error occurs, the performance degradation problem due to interference is relatively less compared to the control channel.

Hereinafter, dynamic spectrum sharing will be described. A scenario in which LTE and 5G systems are deployed and operated in the same frequency band or frequency domain in overlapping frequency bands may be referred to as dynamic spectrum sharing (DSS) or LTE-NR coexsistence. In a system operating DSS, whether to schedule LTE or 5G to the UE may be adjusted according to changes in LTE traffic and 5G traffic. DSS can be used to promote 5G proliferation without additional frequency allocation by maximizing existing frequencies in the early stage of 5G system installation when LTE traffic gradually decreases and 5G traffic gradually increases. From the point of view of telecommunication service providers, DSS operation enables efficient use of frequencies that have already been secured without wasting them.

11A and 11B are diagrams illustrating the concept of Daynamic spectrum sharing (DSS).

11A shows an example in which LTE and 5G systems overlap in the same frequency band.

Referring to FIG. 11A , the base station may determine when to schedule LTE and when to schedule 5G according to the distribution of LTE traffic and 5G traffic. 11A shows an example in which LTE is scheduled during time period T1 and 5G is scheduled during time period T2.

11B shows an example in which LTE and 5G systems partially overlap in the frequency domain.

Referring to FIG. 11B , FIG. 11B shows an example in which LTE is scheduled in the F1 frequency domain of the T1 time interval and 5G is scheduled in the F2 frequency domain of the T1 time interval. And, FIG. 11B shows an example in which 5G is scheduled in the F3 (= F1+F2) frequency domain during the T2 time period. Although LTE and 5G share time/frequency resources in both FIGS. 11A and 11B, deterioration in transmission/reception performance can be minimized by preventing LTE and 5G from collided in time/frequency resources at any moment.

In order to explain collision avoidance between LTE and 5G in the above-described DSS system, a downlink radio resource structure of the LTE system will be described with reference to FIG. 12 first.

12 is a diagram illustrating a basic structure of a time-frequency resource region of an LTE system. That is, FIG. 12 shows a basic structure of a time-frequency domain, which is a radio resource domain in which data or a control channel is transmitted in downlink of an LTE system, and a mapping relationship between downlink physical channels and signals.

It is basically similar to the 5G system described in FIG. 1, but unlike the 5G system, in LTE, the subcarrier interval is generally fixed at 15 kHz regardless of the frequency band, and time-frequency resources are fixedly occupied by control channels and signals. exist.

(일반적으로

= 7) 개의 OFDM 심벌이 모여 하나의 슬롯을 구성하고, 2개의 슬롯으로 1ms 길이의 하나의 서브프레임을 구성하고, 10개의 서브프레임이 모여 10ms 길이의 라디오프레임을 구성할 수 있다. 주파수 영역에서의 최소 전송 단위는 서브캐리어(subcarrier)(1202)로서, 전체 시스템 전송 대역(system bandwidth)(1203)은 총

개의 서브캐리어로 구성될 수 있다.

는 시스템 전송 대역에 비례하여 값을 가질 수 있다. 시간-주파수영역에서 자원의 기본 단위는 리소스 엘리먼트(Resource Element, RE)(1204)로서 OFDM 심벌 인덱스 및 서브캐리어 인덱스로 나타내어질 수 있다. 리소스 블록(Resource Block (RB) 또는 Physical Resource Block (PRB))(1205, 1206)은 시간영역에서

개의 연속된 OFDM 심벌과 주파수 영역에서

(통상

= 12)개의 연속된 서브캐리어로 정의될 수 있다. 따라서, 하나의 RB는

x

개의 RE로 구성될 수 있다. Referring to FIG. 12 , in FIG. 12 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM symbol 1201,

(Generally

= 7) OFDM symbols may be gathered to configure one slot, two slots may be used to configure one subframe with a length of 1 ms, and 10 subframes may be gathered to form a radio frame with a length of 10 ms. The minimum transmission unit in the frequency domain is a subcarrier (subcarrier) 1202, the entire system transmission bandwidth (system bandwidth) (1203) is a total

It may be composed of subcarriers.

may have a value proportional to the system transmission band. A basic unit of a resource in the time-frequency domain is a resource element (RE) 1204 and may be represented by an OFDM symbol index and a subcarrier index. Resource blocks (Resource Block (RB) or Physical Resource Block (PRB)) 1205 and 1206 in the time domain

In the frequency domain with consecutive OFDM symbols

(Normal

= 12) consecutive subcarriers. Therefore, one RB is

x

It may consist of REs.

The LTE downlink control channel 1210 may be mapped within the first number of N OFDM symbols in a subframe in the time domain and may be transmitted to the UE by being mapped over the entire system transmission band in the frequency domain. The time-frequency region to which the LTE downlink control channel is mapped may be referred to as a “control region”. The base station may vary the value of N for each subframe according to the amount of control information to be transmitted in the current subframe. In general, N = {1, 2, 3}. As the control channel, a Physical Control Format Indicator Channel (PCFICH) including an indicator indicating the value of N, a Physical Downlink Control Channel (PDCCH) including uplink or downlink scheduling information, and uplink data indicating success in reception There may be a Physical HARQ Indicator Channel (PHICH) including HARQ ACK/NACK signals. The PCFICH may be mapped to the first symbol among the first N OFDM symbols of the subframe, and the PDCCH may be mapped over the N OFDM symbols. The PHICH may be mapped across OFDM symbols according to a separate configuration indicated by the base station within the N OFDM symbols.

The LTE downlink physical data channel, PDSCH (Physical Downlink Shared Channel) 1211, is mapped during the remaining subframe period in which the downlink control channel is not transmitted in the time domain, and in the frequency domain is mapped to the frequency domain indicated by the LTE PDCCH. can be transmitted.

The base station may transmit a reference signal (hereinafter referred to as RS) to be referred to for the UE to measure the downlink channel state or to refer to the PDSCH demodulation. The reference signal is also called a pilot signal. RS supports a cell-specific reference signal (CRS) 1212 that can be jointly received by terminals in a cell, and a CSI-RS that supports multiple antennas but uses relatively few resources per antenna port compared to CRS ( Channel Status Information Reference Signal) and a Demodulation Reference Signal (DMRS) referenced by the UE to demodulate a PDSCH scheduled for a predetermined UE. In FIG. 12, only the CRS is shown for convenience.

The DMRS for the PDSCH may be mapped to a pre-arranged position in the time-frequency domain of the PDSCH scheduled by the base station. In the case of CSI-RS, the base station may control and operate the transmission period and the mapping position in the time-frequency domain. On the other hand, the CRS has a characteristic of being repeatedly mapped and transmitted to the RE illustrated in FIG. 12 in every subframe over the entire system transmission band.

Antenna port is a logical concept, and RS is defined for each antenna port and is operated to measure the channel state for each antenna port. If the same RS is transmitted from multiple physical antennas, the UE cannot distinguish each physical antenna and recognizes it as one antenna port.

The CRS is a cell common signal, and the UE may measure the CRS and perform the following operation.

1) The downlink channel state is determined from the CRS and then reported to the base station to support the base station scheduling.

2) It is used as a reference signal for demodulation of the PDSCH received from the base station.

3) It is determined whether the radio link between the base station and the terminal is maintained above a certain level.

4) Supports the base station's handover determination by measuring the CRS of the neighboring cell and reporting it to the base station.

Therefore, irrespective of whether or not PDSCH is transmitted to the UE within a predetermined subframe, the base station may transmit the CRS at a predetermined position in every subframe.

As described above, due to the LTE “control region” and LTE CRS, which frequently occupy the time-frequency domain in the LTE system, a collision avoidance method between LTE and 5G is required when transmitting 5G signals through DSS. Hereinafter, a method for avoiding collision of LTE and 5G signals in a DSS system will be described with reference to FIG. 13 .

13 is a diagram illustrating a method for avoiding collision of LTE and 5G signals in a DSS system.

Referring to FIG. 13 , in FIG. 13 , the horizontal axis represents the time domain and the vertical axis represents the frequency domain, respectively. In the example of FIG. 13 , it is assumed that LTE and 5G systems overlap each other in the frequency domain using the same frequency band. And it is assumed that both LTE and 5G systems use the same subcarrier spacing of 15 kHz. For convenience of explanation, it can be distinguished by adding “LTE” to the channel/signal of the LTE system and “NR” to the channel/signal of the 5G system. For example, a PDCCH for LTE may be referred to as an LTE PDCCH, and a PDCCH for 5G may be referred to as an NR PDCCH.

Reference numeral 1320 denotes a basic structure of the downlink time-frequency domain of the LTE system described in FIG. 12, and indicates that the base station transmits an LTE downlink signal during a time period 1301 (LTE reference 1 subframe). The LTE downlink signal may include an LTE CRS 1304 , an LTE PDCCH 1305 , and an LTE PDSCH 1306 . The LTE PDCCH 1305 may include scheduling information for the LTE PDSCH 1306 . In reference number 1320, the LTE "control region" is exemplified that the first 2 symbols in the subframe.

Reference numeral 1350 denotes a basic structure of the time-frequency domain of the 5G system described in FIG. 1 , in which NR PDCCH 1308 , NR PDSCH 1309 , and NR DMRS 1307 for NR PDSCH are mapped. At reference numeral 1350, an NR PDCCH 1308 may be mapped to the first two symbols in a slot, and an NR PDSCH 1309 scheduled by the NR PDCCH 1308 may be mapped during the remainder of the slot. And the NR DMRS 1307 for the NR PDSCH 1309 may be mapped to the 3rd symbol and the 10th symbol in the slot.

In the example of FIG. 13 , the base station may schedule and transmit the LTE PDSCH according to the structure of reference number 1320 to the LTE terminal during the time period of reference number 1301 . Referring to FIG. 13 , there may be no signal transmitted from the base station to the 5G terminal during the time period 1301 . During the time period of reference number 1302 and reference number 1303, the NR PDSCH 1309 may be scheduled and transmitted to the 5G terminal according to the structure of reference number 1360 and reference number 1370, respectively. In addition, during the time period of reference number 1302 and reference number 1303, the base station may transmit LTE CRS and LTE PDCCH according to the structures of reference numbers 1330 and 1340, respectively. In this case, there may be no LTE PDSCH transmission. Reference number 1340 denotes an LTE MBSFN subframe, and has a feature that the overhead of LTE CRS is relatively small compared to the general subframes of reference numbers 1320 and 1330.

1) LTE and 5G signal collision avoidance method 1: LTE CRS rate matching

In the DSS system, when transmitting a 5G downlink signal to a 5G terminal, the base station avoids the location of the LTE CRS and maps and transmits the 5G downlink signal (LTE CRS rate matching). In addition, the base station informs the 5G terminal of LTE CRS configuration information so that the 5G terminal can receive the 5G downlink signal at an accurate location. The LTE CRS configuration information may include at least some of the following information. The UE may know the mapping position of the LTE CRS from the LTE CRS configuration information.

- v-Shift (0, 1, 2, 3, 4, 5): Mapping offset of LTE CRS from RB boundary in frequency domain, expressed in RE units

- nrofCRS-Ports (1, 2, 4): Number of LTE CRS antenna ports

- carrierFreqDL (0 ... 16383): center frequency of LTE carrier

- carrierBandwidthDL (6, 15, 25, 75, 100): LTE carrier bandwidth, expressed in RB units

- mbsfn-SubframeConfigList (period, offset): LTE MBSFN subframe configuration information, including the configuration period and timing offset of the LTE MBSFN subframe

In the example of FIG. 13, when there is no downlink data to be transmitted by the base station to the LTE terminal during the period of reference number 1302, or when the base station determines that scheduling for the 5G terminal is prioritized, the base station allocates the available radio resources to the 5G terminal. can As described above, even if there is no LTE PDSCH to be transmitted to the LTE terminal during a predetermined LTE subframe period, the LTE system maps the LTE CRS to a predetermined location and transmits it. Therefore, when the base station intends to provide a 5G service to the 5G terminal during the period of reference number 1302 (eg, NR PDSCH transmission), the base station maps the NR PDSCH to a time-frequency resource other than the mapping location of the LTE CRS and transmits it. For example, the region indicated by 'x' of reference number 1312 is an RE in which the LTE CRS 1304 of reference number 1320 and reference number 1330 is transmitted, and the base station maps the NR PDSCH to a region other than the corresponding RE and transmits it. Since the UE needs to know the location of the LTE CRS to receive the NR PDSCH except for the RE when receiving the NR PDSCH, the UE obtains LTE CRS configuration information from the base station through signaling.

2) LTE and 5G signal collision avoidance method 2: NR PDCCH mapping adjustment

The time-frequency resource to which the NR PDCCH, which is the downlink control channel of the 5G system, is mapped may be referred to as a control resource set (CORESET). CORESET may be set to all or some frequency resources of a bandwidth supported by the UE in the frequency domain. In the time domain, one or a plurality of OFDM symbols may be set, which may be defined as a CORESET length (Control Resource Set Duration). The base station may set one or a plurality of CORESETs to the terminal through higher layer signaling (eg, system information, master information block (MIB), radio resource control (RRC) signaling). Setting the CORESET to the UE may mean providing information such as a CORESET identifier, a frequency position of the CORESET, and a symbol length of the CORESET. The information provided by the base station to the terminal to set the CORESET may include at least some of the information included in <Table 4>.

RB들로 구성될 수 있고, 시간 영역에서

∈{1,2,3} 심볼로 구성될 수 있다. NR PDCCH 는 하나 혹은 복수개의 CCE (Control Channel Element) 로 구성될 수 있다. 하나의 CCE는 6개의 REG (Resource Element Group)로 구성될 수 있고, REG는 1 OFDM 심볼 동안의 1 RB로 정의될 수 있다. 하나의 CORESET 내에서 REG는 CORESET 의 첫번째 OFDM 심볼, 가장 낮은 RB에서부터 REG 인덱스 0을 시작으로 시간-우선(Time-First) 순서로 인덱스가 매겨질 수 있다.CORESET is in the frequency domain.

may be composed of RBs, and in the time domain

It may be composed of ∈{1,2,3} symbols. The NR PDCCH may consist of one or a plurality of Control Channel Elements (CCEs). One CCE may consist of 6 resource element groups (REGs), and a REG may be defined as 1 RB for 1 OFDM symbol. In one CORESET, REGs may be indexed in time-first order, starting with REG index 0 from the first OFDM symbol of CORESET, the lowest RB.

In 5G, an interleaved method and a non-interleaved method may be supported as a transmission method for the NR PDCCH. The base station may set whether to transmit interleaving or non-interleaving for each CORESET to the terminal through higher layer signaling. Interleaving may be performed in units of REG bundles. A REG bundle may be defined as a set of one or a plurality of REGs. The UE may determine the CCE-to-REG mapping method in the corresponding CORESET based on whether interleaving or non-interleaving transmission configured from the base station is performed in the manner shown in Table 5 below.

In the 5G system, the base station may inform the terminal to which symbol the NR PDCCH is mapped in the slot and configuration information such as the transmission period through signaling.

In the example of FIG. 13 , in the case of reference number 1350 , the NR PDCCH 1308 may be mapped to the first two symbols in the slot and transmitted. During the reference number 1302 time interval in which LTE and 5G coexist, according to reference number 1360, avoiding the time-frequency resources occupied by LTE PDCCH and LTE CRS and mapping NR PDCCH to the third symbol in the slot (1310) By mapping (1310) LTE and 5G collisions can be avoided.

3) LTE and 5G signal collision avoidance method 3: DMRS position adjustment for NR PDSCH

In the 5G system, the base station sets the mapping location of the DMRS for NR PDSCH and informs the terminal by signaling. For example, in the case of reference number 1350 of FIG. 13, DMRS for NR PDSCH may be mapped to the 3rd and 10th symbols in the slot. During the reference number 1302 time period in which LTE and 5G coexist, according to reference number 1360, the time-frequency resources occupied by the LTE PDCCH and LTE CRS are avoided to avoid the 4th and 10th symbols in the slot. DMRS for NR PDSCH is mapped (1313) ), the collision between LTE and 5G can be avoided.

4) Collision avoidance method of LTE and 5G signals 4: Adjust mapping of NR PDSCH

In the 5G system, the base station informs the time-frequency resource information of the NR PDSCH through the NR PDCCH scheduling the NR PDSCH.

For example, in the case of reference number 1350 of FIG. 13 , the NR PDSCH may be mapped from the 3rd symbol to the 14th symbol in the slot. During the reference number 1302 time interval in which LTE and 5G coexist, according to reference number 1360, avoiding the time-frequency resource occupied by the LTE PDCCH and mapping the NR PDSCH from the 4th symbol to the 14th symbol in the slot by mapping (1311), Collision between LTE and 5G can be avoided. NR PDSCH and LTE CRS may be collided with each other through collision avoidance method 1 of LTE and 5G signals.

5) LTE and 5G signal collision avoidance method 5: LTE MBSFN subframe adjustment

By setting MBSFN for a predetermined subframe in the LTE system (LTE MBSFN subframe), the mapping frequency of LTE CRS within the LTE MBSFN subframe is lowered and the time domain size of the LTE “control region” can be limited. That is, the LTE CRS mapping symbol of the LTE MBSFN subframe is limited to within the first 2 symbols within the subframe, and the time domain size of the LTE “control region” of the LTE MBSFN subframe may be limited within the first 2 symbols within the subframe. Reference number 1340 exemplifies that the time period 1303 is set as the LTE MBSFN subframe of the LTE system. Therefore, for the coexistence of LTE and 5G in the time period 1303, the LTE CRS and LTE "control region" mapped over the first 2 symbols of the LTE MBSFN subframe may be mapped to avoid the 5G signal. That is, according to reference number 1370, the NR PDCCH is mapped to the 3rd symbol in the slot by avoiding the time-frequency resource occupied by the LTE PDCCH, and the DMRS for the NR PDSCH is mapped to the 4th and 10th symbols in the slot. Collision of the LTE and 5G signals can be avoided by mapping the NR PDSCH from the 4th symbol to the 14th symbol.

6) LTE and 5G signal collision avoidance method 6: 5G uplink transmission frequency shift

The frequency domain mapping of the 5G uplink signal is deviated from the frequency domain mapping of the LTE uplink signal by 1/2 subcarrier spacing based on the subcarrier spacing of 15 kHz, unless otherwise specified. Therefore, for the coexistence of LTE and 5G signals in the uplink during the time periods 1302 and 1303 of FIG. 13, the frequency domain mapping of the 5G uplink signal is shifted by 1/2 subcarrier interval (=7.5 kHz) to be mapped. can The base station notifies the terminal through signaling that the mapping of the uplink signal is shifted by 7.5 kHz in the frequency domain.

Since the DSS system is a method in which LTE and 5G share time-frequency resources, if 5G traffic is excessively large, a scheduling constraint may occur due to insufficient radio resources for scheduling LTE terminals. Conversely, when LTE traffic is excessively large, a scheduling constraint may occur due to insufficient radio resources for scheduling the 5G terminal. In particular, due to the limitations of the NR PDCCH resource mapping scheme, radio resources for the NR PDCCH may be relatively insufficient compared to the NR PDSCH.

Hereinafter, through a specific embodiment of the present invention, in order to overcome the scheduling constraint for a 5G terminal, a cell to which DSS is applied (hereinafter, referred to as a DSS cell for convenience of description) and a 5G cell are 5G carrier aggregation. After application, a method for cross-carrier scheduling of a 5G cell to a DSS cell will be described.

<First embodiment>

The first embodiment describes a method for the UE to search for an NR PDCCH when a DSS cell and a 5G cell are bundled with carriers and the 5G cell performs cross carrier scheduling for the DSS cell.

First, a search space of the NR PDCCH will be described as follows. The number of CCEs required to transmit the NR PDCCH may be 1, 2, 4, 8, or 16 according to an aggregation level (AL), and the number of different CCEs is a link adaptation of a downlink control channel. can be used for For example, when AL=L, one downlink control channel may be transmitted through L CCEs. The terminal performs blind decoding for detecting a signal in a state where it does not know information about the downlink control channel. For this, a search space representing a set of CCEs may be defined. The search space is a set of downlink control channel candidates consisting of CCEs that the UE should attempt to decode on a given aggregation level, and various aggregations that make one bundle with 1, 2, 4, 8, 16 CCEs Since there is a level, the terminal may have a plurality of search spaces. A search space set may be defined as a set of search spaces in all set aggregation levels.

The search space can be classified into a common search space (CSS) and a UE-specific search space (USS). A group of terminals or all terminals can monitor the common search space of the NR PDCCH in order to receive cell common control information such as dynamic scheduling or paging messages for system information (System Information Blcok, SIB). have. For example, the UE may receive scheduling allocation information of the NR PDSCH for system information reception by examining the common search space of the NR PDCCH. In the case of the common search space, since a certain group of terminals or all terminals need to receive the NR PDCCH, it may be defined as a set of pre-arranged CCEs. The UE-specific scheduling assignment information for the NR PDSCH or NR PUSCH may be received by the UE by examining the UE-specific search space of the NR PDCCH. The UE-specific search space may be UE-specifically defined as a function of the UE's ID (Identity) and various system parameters.

In the 5G system, the base station may configure the configuration information for the search space of the NR PDCCH to the terminal through higher layer signaling (eg, SIB, MIB, RRC signaling). For example, the base station is the number of NR PDCCH candidates in each aggregation level L, the monitoring period for the search space, the monitoring occasion in symbol units in the slot for the search space, and the search space type (common search space or terminal-specific search space) , a combination of a DCI format and an RNTI to be monitored in the corresponding search space, and a CORESET index for monitoring the search space may be set to the UE. For example, the parameter for the search space for the NR PDCCH may include information as shown in Table 6 below.

According to the configuration information, the base station may set one or a plurality of search space sets to the terminal. According to some embodiments, the base station may set the search space set 1 and the search space set 2 to the terminal. In search space set 1, the UE may be configured to monitor DCI format A scrambled with X-RNTI in the common search space, and in search space set 2, the UE uses DCI format B scrambled with Y-RNTI in the UE-specific search space. can be set to monitor.

According to the configuration information, one or a plurality of search space sets may exist in the common search space or the terminal-specific search space. For example, the search space set #1 and the search space set #2 may be set as the common search space, and the search space set #3 and the search space set #4 may be set as the terminal-specific search space.

In the common search space, the UE may monitor a combination of the following DCI format and RNTI. Of course, it is not limited to the following examples.

- DCI format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

- DCI format 2_0 with CRC scrambled by SFI-RNTI

- DCI format 2_1 with CRC scrambled by INT-RNTI

- DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

- DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

In the UE-specific search space, the UE may monitor a combination of the following DCI format and RNTI. Of course, it is not limited to the following examples.

- DCI format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

- DCI format 1_0/1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

The RNTIs may follow the following definitions and uses.

C-RNTI (Cell RNTI): UE-specific PDSCH or PUSCH scheduling purpose

TC-RNTI (Temporary Cell RNTI): UE-specific PDSCH scheduling purpose

CS-RNTI (Configured Scheduling RNTI): Semi-statically configured UE-specific PDSCH scheduling purpose

RA-RNTI (Random Access RNTI): Used for scheduling PDSCH in the random access phase

P-RNTI (Paging RNTI): Used for scheduling PDSCH in which paging is transmitted

SI-RNTI (System Information RNTI): Used for scheduling PDSCH in which system information is transmitted

INT-RNTI (Interruption RNTI): Used to inform whether PDSCH is punctured

TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power control command for PUSCH

TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to indicate power control command for PUCCH

TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to indicate power control command for SRS

The above-described DCI formats may follow the definitions shown in Table 7 below.

The search space of the aggregation level L in the CORESET p in 5G and the search space set s can be expressed by the following equation.

- L: Aggregation level

-n _CI : carrier (Carrier) index

- N _CCE,p : The total number of CCEs present in the control resource set p

- n ^μ _s,f : slot index

- M ^(L) _{p, s, max} : the number of PDCCH candidates of the aggregation level L

- m _snCI = 0, … , M ^(L) _{p, s, max} -1: PDCCH candidate index of aggregation level L

- i = 0, … , L-1

,

,

,

,

,

-

,

,

,

,

,

- n _RNTI : terminal identifier

값은 공통 탐색공간의 경우 0에 해당할 수 있다.

The value may correspond to 0 in the case of a common search space.

값은 단말-특정 탐색공간의 경우, 단말의 ID (C-RNTI 또는 기지국이 단말에게 설정해준 ID)과 시간 인덱스에 따라 변하는 값에 해당할 수 있다.

In the case of a terminal-specific search space, the value may correspond to a value that changes depending on the terminal's ID (C-RNTI or ID set for the terminal by the base station) and the time index.

Hereinafter, when a DSS cell and a 5G cell are bundled with carriers and a 5G cell (SCell) cross-carrier scheduling a DSS cell (PCell), which is the main gist of the first embodiment, a search space of the NR PDCCH is configured, and the UE configures the search space in the search space. A method of receiving the NR PDCCH is described with reference to FIGS. 14 to 16 .

In the examples of FIGS. 14, 15 and 16 , the relationship between whether a cell in which a search space of an NR PDCCH scheduling a predetermined NR PDSCH/NR PUSCH is arranged is a PCell or an SCell may be indicated by an arrow. For example, the start point of the arrow indicates a cell in which the search space of the NR PDCCH is arranged, and the end point of the arrow indicates a cell in which the NR PDSCH/NR PUSCH scheduled by the NR PDCCH is transmitted. The first embodiment assumes that the 5G terminal recognizes the DSS cell as the PCell by connecting to the DSS cell through initial access, and then additionally configures the 5G cell as the SCell.

14 is a diagram illustrating a search space after an initial access of a terminal in a wireless communication system according to an embodiment of the present disclosure. For example, FIG. 14 shows that a 5G terminal connects to a DSS cell (PCell) through initial access and configures an NR PDCCH search space (1401) in the DSS cell. And, the NR PDCCH search space may be composed of a common search space and a UE-specific search space, respectively. 14 shows a state in which there is no search space for SCell because the SCell has not yet been additionally set.

15 is a diagram illustrating a method of configuring an NR PDCCH search space when an SCell is additionally configured in a UE and cross-carrier scheduling of a PCell is performed from the SCell according to an embodiment of the present disclosure. As described above, since the common search space is used for scheduling system information or paging messages, it is preferable to deploy and operate the PCell. Therefore, in the first embodiment, even if the SCell is cross-carrier scheduling the PCell, the common search space of the PCell can be deployed in the PCell (ie, the DSS cell) as it is ( 1501 ). On the other hand, the UE-specific search space of the PCell is moved to the SCell, so that the aforementioned lack of radio resources for the NR PDCCH in the DSS cell (PCell) can be solved ( 1502 ). Accordingly, there is no longer a UE-specific search space for a PCell in the PCell. And a search space for scheduling the SCell is arranged in the SCell (1503).

As a modified example of the first embodiment, it is possible to move and arrange the search space of the PCell to the SCell and still maintain a part of the search space of the PCell in the PCell. For example, the PCell maintains a common search space and UE-specific search space for scheduling the PCell (1501), and the SCell has a UE-specific search space 1502 for cross-carrier scheduling of the PCell and self-carrier scheduling of the SCell. A search space is set up to do this (1503). Accordingly, the base station has a feature that can transmit the NR PDCCH for the PCell through the search space of the remaining stable radio link even if either one of the PCell and the SCell radio link is unstable.

Various modifications are possible for the above-described NR PDCCH search space configuration. For example, the setting of the search space for the PCell and the CORESET setting, which the UE investigates in the SCell, can be realized in various ways as follows.

- Method of setting the search space and CORESET for the PCell in the SCell 1: The setting of the search space for the PCell and the CORESET setting that the UE investigates in the SCell follow the same setting of the UE-specific search space for the SCell and the CORESET setting, respectively.

- Method of setting the search space and CORESET for the PCell in the SCell 2: The setting of the search space for the PCell and the CORESET setting, which the UE investigates in the SCell, set a predetermined offset compared to the setting of the UE-specific search space for the SCell and the CORESET setting, respectively. apply The offset is notified by the base station to the terminal through signaling.

- Method of setting the search space and CORESET for the PCell in the SCell 3: The setting of the search space for the PCell and the CORESET setting that the UE investigates in the SCell requires separate settings independent of the setting of the UE-specific search space for the SCell and the CORESET setting. have Accordingly, the base station notifies the terminal of the configuration of the search space for the PCell and the CORESET configuration that the terminal investigates in the SCell through signaling.

- Method of setting the search space and CORESET for PCell in the SCell 4: The base station notifies the UE through signaling which method among Methods 1, 2, and 3 to be used for setting the search space and CORESET for the PCell in the SCell.

With respect to the NR PDCCH search space configured as shown in FIG. 15, the UE needs a method of identifying which cell the NR PDSCH/NR PUSCH of the NR PDCCH received from the base station is scheduled. For example, referring to FIG. 15 , the UE obtains an NR PDCCH 1504 obtained by investigating (monitoring) the NR PDCCH search space 1501 of the PCell, and the NR PDCCH search space 1502 of the SCell obtained by examining the NR PDCCH search space 1502. For the NR PDCCH 1505 and the NR PDCCH 1506 obtained by examining the NR PDCCH search space 1503 of the SCell, there is a need for a method of distinguishing which cell each NR PDSCH/NR PUSCH is scheduled. Accordingly, in the present invention, the base station transmits the NR PDCCH including a carrier indicator field (CIF) to the terminal, and the terminal receives the NR PDCCH from the cell information in which the NR PDCCH search space is set and the CIF of the NR PDCCH, It determines whether NR PDSCH/NR PUSCH is scheduled. The cell information in which the NR PDCCH search space is configured may be a cell index (or carrier index), frequency information to which the NR PDCCH is mapped, or a search space index. Accordingly, the cell in which the NR PDSCH/NR PUSCH scheduled by the NR PDCCH is transmitted can be generalized and expressed as in the following equation.

In the above equation, the function f(.) is a generalized function for calculating cell information from the input parameters.

Hereinafter, a method for determining cell information on which NR PDSCH/NR PUSCH scheduled by NR PDCCH are transmitted will be described in detail in a carrier aggregation environment. For convenience of explanation, referring to FIG. 15 , the NR PDCCH 1504 transmitted in the NR PDCCH search space 1501 of the PCell includes CIF = 'X', and is transmitted in the NR PDCCH search space 1502 of the SCell. It is assumed that the NR PDCCH 1505 includes CIF = 'Y', and the NR PDCCH 1506 transmitted in the NR PDCCH search space 1503 of the SCell includes CIF = 'Z'.

- Method 1 for determining a cell in which the NR PDSCH/NR PUSCH is transmitted: Method 1 includes the CIF in the NR PDCCH regardless of whether the cell in which the NR PDCCH is transmitted is a PCell or an SCell. And even if the cells in which the NR PDCCH are transmitted are different (1504, 1505), if the NR PDSCH/NR PUSCH scheduled by the respective NR PDCCHs are transmitted in the same cell (1507), the CIF values of the NR PDCCHs are the same. Set (X=Y). Also, although the NR PDCCH 1505 and the NR PDCCH 1506 transmitted in the same SCell, the NR PDSCH/NR PUSCH 1507 and 1508 transmitted in different cells are scheduled to be distinguished. ) and CIF of the NR PDCCH 1506 are set to different values. (Y≠Z)

15, CIF (X, Y, Z) of method 1 may be set to (0, 0, 1), respectively. That is, since all of the cells in which the NR PDSCH/NR PUSCH 1507 scheduled by the NR PDCCH 1504 and the NR PDCCH 1505 are transmitted are identical to the PCell, the CIF value is set to X=Y, and additionally the In this case, the case of X=Y=0 is indicated by displaying the CIF value as '0'. The PCell is a basic cell for the UE and is set to CIF = 0 in order to give a higher priority than the SCell. In addition, since the cell in which the NR PDSCH/NR PUSCH 1508 scheduled by the NR PDCCH 1506 is transmitted is an SCell, not a PCell, it represents a case where Z = 1 different from the CIF value for the PCell. From the received CIF values of NR PDCCH 1504, NR PDCCH 1505, and NR PDCCH 1506, the UE receives NR PDCCH 1504 and NR PDCCH 1505 with CIF = '0' is NR PDSCH/ It is determined that the NR PUSCH 1507 is scheduled, and the NR PDCCH 1506 with CIF = '1' is determined to schedule the NR PDSCH/NR PUSCH 1508 of the SCell. In addition, since the NR PDCCH 1504 and the NR PDCCH 1505 have a search space separated into a PCell and an SCell, respectively, the UE can distinguish them.

- Method 2: Determining a cell in which NR PDSCH/NR PUSCH is transmitted: In Method 2, the CIF is included in the NR PDCCH regardless of whether the cell in which the NR PDCCH is transmitted is a PCell or an SCell. And if the cells in which the NR PDCCH is transmitted are different (1504, 1505), and the NR PDSCH/NR PUSCH scheduled by each NR PDCCH is transmitted in the same cell (1507), the CIF value of the NR PDCCH is set differently. Distinguish (X≠Y). Also, although the NR PDCCH 1505 and the NR PDCCH 1506 transmitted in the same SCell, the NR PDSCH/NR PUSCH 1507 and 1508 transmitted in different cells are scheduled to be distinguished. ) and CIF of the NR PDCCH 1506 are also set to different values. (Y≠Z)

15, CIF (X, Y, Z) of method 2 may be set to (0, 1, 0), respectively. That is, the cells in which the NR PDCCH 1504 and the NR PDCCH 1505 are transmitted are different from each other as PCell and SCell, but NR PDSCH/NR PUSCH 1507 scheduled by the NR PDCCH 1504 and NR PDCCH 1505 Since all cells in which P is transmitted are identical to the PCell, the CIF values of the NR PDCCH 1504 and the NR PDCCH 1505 are set to different values (X≠Y). By displaying '0', the case where X=0 and Y=1 is represented. The PCell is a basic cell for the UE and is set to CIF X=0 of the NR PDCCH transmitted from the PCell in order to give a higher priority than the SCell. And, although the NR PDCCH 1505 and the NR PDCCH 1506 transmitted in the same SCell, the scheduling of the NR PDSCH/NR PUSCH 1507 and 1508 transmitted in different cells is distinguished. and CIF of the NR PDCCH 1506 are set to different values. (Y≠Z, Y=1, Z=0)

The UE determines to schedule the NR PDSCH/NR PUSCH 1507 of the PCell from the NR PDCCH 1504 received from the PCell for the received NR PDCCH 1504, NR PDCCH 1505, and NR PDCCH 1506 do. And from the CIF values of the NR PDCCH 1505 and NR PDCCH 1506 received from the SCell, the NR PDCCH 1505 with CIF = '1' schedules the NR PDSCH/NR PUSCH 1507 of the PCell according to a prior arrangement. and determines that the NR PDCCH 1506 with CIF = '0' schedules the NR PDSCH/NR PUSCH 1508 of the SCell.

- Method 3 for determining a cell in which NR PDSCH/NR PUSCH is transmitted: In method 3, when a cell in which NR PDCCH is transmitted is an SCell, a CIF is included in the NR PDCCH. If the NR PDCCH is transmitted in the PCell, the CIF is not included in the NR PDCCH (X=NULL). In addition, although the NR PDCCH 1505 and the NR PDCCH 1506 transmitted in the SCell, the NR PDSCH/NR PUSCH 1507 and 1508 transmitted in different cells are scheduled to be distinguished. The CIF of the NR PDCCH 1506 is set to different values. (Y≠Z)

15, CIF (X, Y, Z) of method 3 may be set to (NULL, 0, 1), respectively. The UE receives the NR PDCCH 1504, NR PDCCH 1505, and NR PDCCH 1506 according to the CIF configuration as described above, from the NR PDCCH 1504 received from the PCell to the NR PDSCH/NR PUSCH 1507 of the PCell. ) to determine whether to schedule And from the CIF values of the NR PDCCH 1505 and NR PDCCH 1506 received from the SCell, the NR PDCCH 1505 with CIF = '0' schedules the NR PDSCH/NR PUSCH 1507 of the PCell according to a prior arrangement. and determines that the NR PDCCH 1506 with CIF = '1' schedules the NR PDSCH/NR PUSCH 1508 of the SCell.

- Method 4: Determining a cell in which NR PDSCH/NR PUSCH is transmitted: Method 4 includes CIF for NR PDCCHs 1504 and 1505 scheduling NR PDSCH/NR PUSCH 1507 of the PCell. And the NR PDCCH 1506 scheduling the NR PDSCH/NR PUSCH 1508 of the SCell does not include a CIF (Z=NULL). The NR PDCCH 1504 and the NR PDCCH 1505 including the CIF set different CIF values to distinguish which cell is scheduled (X≠Y). Alternatively, the same CIF value may be set (X=Y) in the NR PDCCH 1504 and the NR PDCCH 1505 including the CIF. In this case, since the NR PDCCH search space is (1501, 1502) divided into PCell and SCell, respectively, even if the same CIF value is set, which cell is scheduled can be distinguished (X=Y).

15, CIF (X, Y, Z) of method 4 may be set to (0, 0, NULL), respectively. The UE determines that the NR PDCCHs 1504 and 1505 schedule the NR PDSCH/NR PUSCH 1507 from the CIF values of the NR PDCCH 1504 and the NR PDCCH 1505 and the cell information to which the search space belongs. . Then, from the CIF configuration (NULL) of the NR PDCCH 1506 and the search space, it is determined that the NR PDCCH 1506 schedules the NR PDSCH/NR PUSCH 1508 .

- Method 5: Determining a cell in which NR PDSCH/NR PUSCH is transmitted: In Method 5, the base station determines which method among Methods 1 to 4 to apply, and informs the UE through signaling.

With respect to Methods 1 to 5 described above, the search space 1502 of the NR PDCCH 1505 and the search space 1503 of the NR PDCCH 1506 existing in the SCell are each independently mapped to separate resource regions, or some Alternatively, they may be mapped by sharing all resources with each other.

The main points of the above-described methods 1 to 4 are summarized in Table 8 below.

16 is a diagram illustrating a method for a UE to monitor an NR PDCCH search space in a wireless communication system according to an embodiment of the present disclosure. That is, FIG. 16 shows a procedure for the UE to monitor the NR PDCCH according to the method for configuring the NR PDCCH search space described in FIG. 15 . In step 1601, the terminal is instructed to set the carrier bundle from the base station. In an embodiment, the carrier bundle configuration may include a configuration in which the SCell performs cross-carrier scheduling of the PCell. For example, the setting may include the following signaling.

1) Signaling 1: PCell ID is indicated as index information of a scheduled cell in which NR PDSCH / NR PUSCH scheduled by NR PDCCH are transmitted, or

2) Signaling 2: The SCell explicitly indicates that the PCell is cross-carrier scheduling

When the terminal completes the carrier bundle configuration according to the instruction of the base station, the terminal may perform NR PDCCH monitoring in step 1602 . For example, according to the configuration of the NR PDCCH search space, the UE may search for a search space for PCell in PCell and search {search space for PCell, search space for SCell} in SCell. The setting of the search space for the PCell and the CORESET setting that the UE investigates in the SCell may follow the setting of the search space for the SCell and the CORESET setting, or may follow a separate independent setting. In a later step, the UE may receive the NR PDSCH or transmit the NR PUSCH according to the scheduling of the successfully received NR PDCCH. In this case, the UE determines which cell to receive the NR PDSCH from or which cell to transmit the NR PUSCH to according to the above-described 'method for determining a cell in which NR PDSCH/NR PUSCH is transmitted'.

Various modifications are possible in the first embodiment. As an example, the CIF configuration may be different by dividing the search space of the NR PDCCH. A CIF may not be separately added to an NR PDCCH mapped to a common search space and transmitted, but a CIF may be added to an NR PDCCH mapped and transmitted to a UE-specific search space. Therefore, the NR PDCCH of the common search space has a characteristic that the configuration of control information is consistently maintained regardless of whether or not a carrier bundle is set.

As another example, the CIF configuration may be different by dividing the DCI format constituting the NR PDCCH. For example, the CIF may not be separately added to the DCI format 0_0/1_0, and the CIF may be added to the DCI format 0_1/1_1. Accordingly, the DCI format 0_0/1_0 has a characteristic that the configuration of control information is consistently maintained regardless of whether or not a carrier bundle is set.

<Second embodiment>

The second embodiment describes a method of adaptively changing a cell transmitting an NR PDCCH when a DSS cell and a 5G cell are bundled with a 5G carrier and the 5G cell performs cross carrier scheduling of the DSS cell.

In the configuration of the NR PDCCH search space in which the aforementioned search space for PCell exists in both the PCell and the SCell, an additional procedure related to the HARQ operation of the NR PDSCH / NR PUSCH of the PCell may be required. For example, the NR PDCCH scheduling the NR PDSCH of the PCell at a predetermined moment is mapped to the search space for the PCell of the SCell and transmitted, and the NR PDCCH scheduling the NR PDSCH of the PCell at another predetermined moment is in the search space for the PCell of the PCell. It can be mapped and transmitted (or vice versa).

Hereinafter, the second embodiment will be described in detail with reference to FIG. 17 . 17 shows a case in which the SCell 1701 performs cross-carrier scheduling of the PCell 1702 in three A, B, and C methods. In FIG. 17 , the horizontal axis represents time, the start point of the arrow indicates a cell in which the search space of the NR PDCCH is arranged, and the end point of the arrow indicates a cell in which the NR PDSCH/NR PUSCH scheduled by the NR PDCCH is transmitted. For convenience of explanation, scheduling in units of slots 1703 is exemplified, but the present invention is not limited to scheduling in units of slots. In FIG. 17, each slot of the PCell or SCell is denoted by (x, y), x is a cell index, x = 0 indicates a PCell, and x = 1 indicates an SCell. And y is a slot index, y=0 indicates the 0th slot, y=1 indicates the first slot, and indicates that the slot index value increases as time passes.

- Method A: Method A shows a case in which there is no restriction in transmitting the NR PDCCH in the SCell for cross-carrier scheduling of the PCell. Therefore, in the case of A of FIG. 17, by transmitting the NR PDCCH in the slot (1,0) of the SCell during the time period T0, in the slot (0,0) of the PCell temporally corresponding to the slot (1,0) of the SCell Cross-carrier scheduling of NR PDSCH/NR PUSCH to be transmitted. NR PDSCH to be transmitted in the slot (0,1) of the PCell temporally corresponding to the slot (1,1) of the SCell by sequentially transmitting the NR PDCCH in the slot (1,1) of the SCell during the time period T1 Cross-carrier scheduling of NR PUSCH. That is, all of the slots (1,0) and (1,1) of the SCell indicate that downlink radio resources are secured to the extent that there is no restriction in transmitting the NR PDCCH. For example, all of the slots (1,0) and (1,1) of the SCell may be downlink slots. In the case of method A, the UE investigates the corresponding NR PDCCH search interval of the SCell over time intervals T0 and T1 to obtain the NR PDCCH scheduling the PCell.

- Method B: Method B shows a case where there is a restriction in transmitting the NR PDCCH in an SCell that performs cross-carrier scheduling of the PCell. Referring to B of FIG. 17 , a case in which downlink radio resources are not secured to such an extent that the slot (1,1) (reference number 1704) of the SCell has a restriction in transmitting the NR PDCCH is shown. For example, the slot (1,1) (reference number 1704) of the SCell indicates that it is configured as an uplink slot. Therefore, during time period T0, the NR PDCCH transmitted in the slot (1,0) of the SCell is the NR PDSCH/NR PUSCH to be transmitted in the slot (0,0) of the PCell temporally corresponding to the slot (1,0) of the SCell. is cross-carrier scheduling. Additionally, method B cross-carrier scheduling NR PDSCH/NR PUSCH to be transmitted in slot (0,1) of PCell of time interval T1 by NR PDCCH transmitted in slot (1,0) of SCell in time interval T0. . That is, since the slot (1,1) of the SCell temporally corresponding to the slot (0,1) of the PCell is no longer able to transmit the NR PDCCH, the slot (0,1) of the PCell (ie, the time period T1) The NR PDCCH for cross-carrier scheduling of the PCell is transmitted in the slot (1,0) (time interval T0) of the preceding SCell. Through this, it is possible to obtain the effect of maximally utilizing the radio resources of the NR PDSCH/NR PUSCH transmitted from the PCell. In the case of method B, the UE investigates the corresponding NR PDCCH search period of the SCell in time period T0 to obtain the NR PDCCH scheduling the PCell, and does not investigate the corresponding NR PDCCH search period of the SCell in time period T1.

- Method C: Method C shows a case where there is a restriction in transmitting NR PDCCH in an SCell that performs cross-carrier scheduling of a PCell. Referring to C of FIG. 17 , a case in which downlink radio resources are not secured to such a degree that the slot (1,1) (reference number 1705) of the SCell has a restriction in transmitting the NR PDCCH is shown. For example, the slot (1,1) (reference number 1705) of the SCell indicates that it is configured as an uplink slot. Therefore, in the time period T0, the NR PDCCH transmitted in the slot (1,0) of the SCell is the NR PDSCH/NR to be transmitted in the slot (0,0) of the PCell temporally corresponding to the slot (1,0) of the SCell. Cross-carrier scheduling of PUSCH. In addition, method C self-carrier scheduling NR PDCCH transmitted in slot (0,1) of PCell and NR PDSCH/NR PUSCH to be transmitted in slot (0,1) of PCell in time period T1. That is, since NR PDCCH transmission is no longer possible in the slot (1,1) of the SCell that is temporally corresponding to the slot (0,1) of the PCell in the time period T1, even though the PCell is set in advance for cross-carrier scheduling. However, exceptionally, the NR PDCCH for self-carrier scheduling of the PCell is transmitted in the slot (0,1) of the PCell. Through this, it is possible to obtain the effect of maximally utilizing the radio resources of the NR PDSCH/NR PUSCH transmitted from the PCell. In the case of method C, the UE investigates the corresponding NR PDCCH search interval of the SCell in time interval T0 (that is, cross-carrier scheduling) to obtain the NR PDCCH scheduling the PCell, and in time interval T1, the UE searches the corresponding NR PDCCH of the PCell. Investigate the search interval (ie, self-carrier scheduling). The switching between cross-carrier scheduling and self-carrier scheduling is performed by the UE when a predetermined condition is satisfied such as when the base station instructs the UE through explicit signaling or the downlink radio resource of the SCell is insufficient as in the example of FIG. 17 . can be judged as

For Method B and Method C described above, the BS includes at least the following information in the NR PDCCH for scheduling the PCell, thereby notifying the UE of which cell and at what time NR PDSCH/NR PUSCH transmission occurs.

- Cell information on which NR PDSCH/NR PUSCH is transmitted: for example, cell index, carrier index

- NR PDSCH/NR PUSCH transmission time information: for example, slot index, NR PDCCH reference timing offset

If there is a restriction in transmitting the NR PDCCH in the SCell for cross-carrier scheduling of the PCell, the base station may select which method to use from the method B and the method C and inform the terminal through signaling.

17 illustrates a case where the subcarrier spacing of the PCell and the SCell to which the carrier bundle is applied is the same, whereas FIG. 18 describes the case where the subcarrier spacing between the PCell and the SCell to which the carrier bundle is applied is different. For example, PCell has a subcarrier spacing of 15 kHz and SCell has a subcarrier spacing of 30 kHz. Accordingly, it represents a case where the slot length of the PCell is longer than the slot length of the SCell by the difference in the subcarrier spacing. The basic operation of FIG. 18 is similar to the case of FIG. 17 .

- Method A: Method A shows a case in which there is no restriction in transmitting the NR PDCCH in the SCell for cross-carrier scheduling of the PCell. Therefore, in the case of A of FIG. 18, by transmitting the NR PDCCH in the slot (1,0) or the slot (1,1) of the SCell in the time interval T0, the slot (1,0) or the slot (1,1) of the SCell Cross-carrier scheduling of NR PDSCH/NR PUSCH to be transmitted in slot (0,0) of PCell temporally corresponding to . Sequentially, by transmitting the NR PDCCH in the slot (1,2) or (1,3) of the SCell during the time period T1, the time corresponding to the slot (1,2) or (1,3) of the SCell in time Cross-carrier scheduling NR PDSCH/NR PUSCH to be transmitted in slot (0,1) of PCell. That is, slots (1,0), (1,1), (1,2), and (1,3) of the SCell all secure downlink radio resources to the extent that there is no restriction in transmitting the NR PDCCH. indicates that For example, slots (1,0), (1,1), (1,2), and (1,3) of the SCell may all be downlink slots. However, the start time of the NR PDCCH transmitted from the SCell must be at least equal to or earlier than the start time of the NR PDSCH/NR PUSCH transmitted from the PCell (hereinafter referred to as 'condition A' for convenience of description). For example, if the NR PDCCH transmitted in the slot (1,1) of the SCell intends to schedule the NR PDSCH of the slot (0,0) of the PCell, the start time of the NR PDSCH may be earlier than the start time of the NR PDCCH. none. Through such a restriction, processing complexity of the terminal may be reduced.

In the case of method A, the UE investigates the corresponding NR PDCCH search interval of the SCell over time intervals T0 and T1 to obtain the NR PDCCH scheduling the PCell.

- Method B: Method B shows a case where there is a restriction in transmitting the NR PDCCH in an SCell that performs cross-carrier scheduling of the PCell. Referring to B of FIG. 18, the downlink radio resources are not secured enough that the slots (1,2) (reference number 1803)/slots (1,3) (reference number 1804) of the SCell have restrictions in transmitting the NR PDCCH. indicates a case where it is not. For example, slots (1,2) (reference number 1803)/slots (1,3) (reference number 1804) of the SCell indicate that it is configured as an uplink slot. Therefore, in the time period T0, the NR PDCCH transmitted in the slot (1,0) or slot (1,1) of the SCell is that of the PCell temporally corresponding to the slot (1,0) or slot (1,1) of the SCell. Cross-carrier scheduling NR PDSCH/NR PUSCH to be transmitted in slot (0,0). Additionally, method B is a method in which NR PDCCH transmitted in slot (1,0) or slot (1,1) of SCell is transmitted in slot (0,1) of PCell in time interval T1 when time interval T0 is NR PDSCH/NR Cross-carrier scheduling of PUSCH. That is, since the slot (1, 2) or (1, 3) of the SCell temporally corresponding to the slot (0,1) of the PCell is no longer capable of NR PDCCH transmission, the slot (0,1) of the PCell ( That is, the NR PDCCH for cross-carrier scheduling of the PCell is transmitted in the slot (1,0) or (1,1) (time period T0) of the SCell preceding the time period T1). Through this, it is possible to obtain the effect of maximally utilizing the radio resources of the NR PDSCH/NR PUSCH transmitted from the PCell. Method B must also satisfy the above 'condition A' like method A. In the case of method B, the UE investigates the corresponding NR PDCCH search period of the SCell in time period T0 to obtain the NR PDCCH scheduling the PCell, and does not investigate the corresponding NR PDCCH search period of the SCell in time period T1.

- Method C: Method C shows a case where there is a restriction in transmitting NR PDCCH in an SCell that performs cross-carrier scheduling of a PCell. Referring to C of FIG. 18 , the downlink radio resources are not secured enough to limit the transmission of the NR PDCCH in slots (1,2) (reference number 1805)/slots (1,3) (reference number 1806) of the SCell. indicates a case where it is not. For example, slots (1,2) (reference number 1805)/slots (1,3) (reference number 1806) of the SCell indicate that it is configured as an uplink slot. Therefore, in the time period T0, the NR PDCCH transmitted in the slot (1,0) or (1,1) of the SCell is the PCell temporally corresponding to the slot (1,0) or (1,1) of the SCell. Cross-carrier scheduling of NR PDSCH/NR PUSCH to be transmitted in slot (0,0) of In addition, method C self-carrier scheduling NR PDCCH transmitted in slot (0,1) of PCell and NR PDSCH/NR PUSCH to be transmitted in slot (0,1) of PCell in time period T1. That is, since the NR PDCCH transmission is no longer possible in the slot (1, 2) or (1, 3) of the SCell temporally corresponding to the slot (0,1) of the PCell in the time period T1, even though the PCell is cross- Even in the case where carrier scheduling is set in advance, the NR PDCCH for self-carrier scheduling of the PCell is transmitted exceptionally in the slot (0,1) of the PCell. Through this, it is possible to obtain the effect of maximally utilizing the radio resources of the NR PDSCH/NR PUSCH transmitted from the PCell. Method C must also satisfy the above 'condition A' like method A. In the case of method C, the UE investigates the corresponding NR PDCCH search interval of the SCell in time interval T0 (ie, cross-carrier scheduling) to obtain the NR PDCCH scheduling the PCell, and in time interval T1, the UE searches the corresponding NR PDCCH of the PCell. Investigate the search interval (ie, self-carrier scheduling). The switching between cross-carrier scheduling and self-carrier scheduling is performed by the UE when a predetermined condition is satisfied such as when the base station instructs the UE through explicit signaling or the downlink radio resource of the SCell is insufficient as in the example of FIG. 18 . can be judged as

Various modifications are possible in the second embodiment. For example, the method B or method C may be applied by dividing the search space of the NR PDCCH. That is, if there is a restriction in transmitting the NR PDCCH in the SCell for cross-carrier scheduling of the PCell, the NR PDCCH transmission is not performed without a separate operation for the common search space, and method B or method C is used for the terminal-specific search space. apply

As another example, the method B or method C may be applied by dividing the DCI format constituting the NR PDCCH. That is, if there is a restriction in transmitting the NR PDCCH in the SCell for cross-carrier scheduling of the PCell, the NR PDCCH transmission is not performed for DCI format 0_0/1_0 without separate operation, and for DCI format 0_1/1_1, the above method B or method apply C.

<Third embodiment>

The third embodiment describes a configuration method for bundling a DSS cell and a 5G cell with a 5G carrier and for the 5G cell to cross-carrier scheduling the DSS cell.

Hereinafter, an operation of setting a carrier bundle to the terminal will be described with reference to FIG. 19 . 19 is a diagram illustrating a procedure for setting a carrier bundle in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 19 , in step 1904 , the terminal 1900 performs initial access to the base station 1901 . In the initial access process, the UE can synchronize downlink time and frequency from a synchronization signal transmitted by the base station through cell search and obtain a cell ID. In addition, the UE may receive a PBCH (Physical Broadcast Channel) by using the obtained cell ID, and may obtain MIB (Master Information Block), which is essential system information, from the PBCH. Additionally, the terminal may receive system information (SIB) transmitted by the base station to obtain control information related to transmission and reception common to the cell. The cell common transmission/reception related control information may include random access related control information, paging related control information, and/or common control information for various physical channels. A cell accessed by the UE in step 1904 may mean a PCell.

In step 1905, the terminal performs random access to the base station by using the random access related control information obtained from the system information. The terminal that has successfully completed the random access procedure may synchronize uplink time with the base station. In addition, one-to-one communication between the base station and the terminal may be enabled by switching the terminal to a connected state.

In step 1906, the terminal performs data transmission and reception with the base station through the PCell 1902. The terminal may report UE capability information to the base station to inform the base station of whether the terminal itself supports a predetermined function, the maximum allowable value of the function supported by the terminal, and the like. The UE capability information may include whether the UE supports a carrier bundle and/or carrier bundle related information. In addition, it may include whether the UE supports the cross-carrier scheduling of the PCell by the SCell, the NR PDCCH discovery method supported by the UE, and the like. In step 1906, the UE may perform a measurement report on neighboring cells. For example, if the received signal strength from neighboring cells observed by the terminal is greater than a predetermined threshold, the ID and the received signal strength of the corresponding cell may be included in the measurement report and transmitted to the base station. The reference signal observed by the UE for measurement report may be an SS/PBCH block or CSI-RS transmitted by a neighboring cell. The base station may inform the terminal of control information for the measurement report of the terminal through signaling. The control information for the measurement report of the terminal may include at least a part of control information related to the following.

- Information about the reference signal of the neighboring cell to be measured. For example, whether it is an SS/PBCH block or CSI-RS

- Subcarrier spacing of the reference signal

- time/frequency domain location of the reference signal

- Start/frequency domain size of the reference signal

- When reporting the measurement result measured by the terminal to the base station, whether to report periodically or based on a predetermined event

The base station may determine whether to set a carrier bundle for the terminal or to instruct handover to another cell with reference to the measurement report of the terminal. The determination of whether to set the carrier bundle may mean determining whether to combine the additional carrier (SCell) 1903 with the PCell 1902 of the current terminal, for example. If the base station determines to perform carrier bundling for the terminal, in step 1907, the base station includes related information (relevant information required for carrier bundling) necessary for SCell binding of the terminal in the 'RRC reconfiguration' message to the terminal can be sent to The related information required for the carrier bundle may include carrier bandwidth and center frequency information of the SCell, and/or common control information for a physical channel of the SCell.

The UE completes a process for performing communication with the SCell according to the received 'RRC reconfiguration' message, and then transmits a 'RRC reconfiguration complete' message to the base station in step 1908. Now, from step 1909, the terminal is in a state of complete preparation to transmit and receive data with both the PCell and the SCell of the base station.

Configuration information for signal transmission and reception between the terminal and the base station may be configured for each cell. In addition, the NR system may set one or more BWP (Bandwidth Part) in one cell, and may adjust the setting between the terminal and the base station for each BWP. BWP refers to a subband allowed from a minimum of 1 RB to a maximum system bandwidth in the frequency domain. The configuration information for the UE to receive the NR PDCCH may include the CORESET configuration information of <Table 4> and/or the search space configuration information of <Table 6>. The configuration information between the terminal and the base station in the cell is configured in a hierarchical structure in the following order.

1) 'SearvingCellConfig' : includes cell-based TDD UL-DL configuration information, BWP configuration information, etc.

2) 'BWP' : frequency domain size/position information of BWP, subcarrier interval information applied to BWP, NR PDCCH configuration information, NR PDSCH configuration information, NR PUSCH configuration information, NR PUCCH configuration information, NR RACH configuration information, etc. include

3) 'PDCCH-Config' : Includes CORESET setting information, Search space setting information, etc.

4) 'CORESET' : Includes CORESET ID, CORESET time/frequency setting information, QCL indicator setting information in DCI, etc.

5) 'SearchSpace' : Search space ID, CORESET ID, NR PDCCH monitoring period/offset, aggregation level, search space type, etc.

20 shows a case in which configuration information related to the NR PDCCH of the hierarchical structure is set to PCell (2001) and SCell (2011), respectively, to a terminal configured to set a carrier bundle. In the case of carrier bundling, the NR PDCCH-related configuration may be configured by the base station to the terminal through, for example, an 'RRC reconfiguration' procedure in step 1907 of FIG. 19 .

Specifically, the method of configuring the NR PDCCH of the SCell for cross-carrier scheduling of the PCell is as follows.

- SCell NR PDCCH setting method 1: Include 'tci-PresentInDCI' in the SCell CORESET setting information (2015) and set the setting value to 'enable'. The meaning of ' tci-PresentInDCI = enable' means that the TCI state control information for adjusting the beam setting (or QCL relationship setting) of the NR PDSCH among the control information configuring the NR PDCCH is included. Accordingly, the configuration of a beam or QCL relationship that may occur due to a difference in channel environment between the SCell through which the NR PDCCH is transmitted and the PCell through which the NR PDSCH is transmitted can be adjusted with the TCI state control information.

The TCI state is for announcing the QCL (Quasi co-location) relationship between the NR PDSCH (or NR PDSCH DMRS) and another RS or channel, and a certain reference antenna port A (reference RS #A) and another destination antenna port B ( To say that target RS #B) are QCLed to each other (QCLed) means that the terminal is allowed to apply some or all of the large-scale channel parameters estimated from the antenna port A to the channel measurement from the antenna port B. can mean QCL is 1) time tracking affected by average delay and delay spread of wireless channel, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) RRM (radio resource management) affected by average gain, 4) Depending on the situation, such as BM (beam management) affected by spatial parameters, it may be necessary to correlate different parameters.

And in Method 1, the search space configuration information (2016) of the SCell and the search space configuration information (2006) of the PCell are set identically. For example, the 'search space ID' value in the search space configuration information (2016) of the SCell is matched with the 'search space ID' value in the search space configuration information (2006) of the PCell. Accordingly, the UE applies the same search space configuration information regardless of whether the NR PDCCH for scheduling the PCell is transmitted from the PCell (ie, self-carrier scheduling) or transmitted from the SCell (ie, cross-carrier scheduling). reduce complexity.

- NR PDCCH setting method of SCell 2: In addition to the configuration of NR PDCCH setting method 1 of the SCell, CORESET setting information (2015) of SCell and CORESET setting information (2005) of PCell are set identically. For example, the 'CORESET ID' value in the CORESET setting information (2015) is matched with the 'CORESET ID' value in the CORESET setting information (2005) of the PCell. Accordingly, the UE applies the same CORESET configuration information regardless of whether the NR PDCCH scheduling the PCell is transmitted from the PCell (ie, self-carrier scheduling) or transmitted from the SCell (ie, cross-carrier scheduling), thereby complicating the NR PDCCH search. reduces the As a modified example of NR PDCCH configuration method 2 of the SCell, CORESET configuration information of the SCell for cross-carrier scheduling of the PCell and other CORESET configuration information of the SCell for self-carrier scheduling of the SCell can be set identically. Through this, the UE applies the same CORESET configuration information regardless of whether the NR PDCCH transmitted from the SCell performs cross-carrier scheduling of PCell or self-carrier scheduling of SCell, thereby reducing the complexity of NR PDCCH search.

- NR PDCCH configuration method of SCell 3: The NR PDCCH configuration of the SCell (2014) and the NR PDCCH configuration of the PCell (2004) are independently configured without any restrictions. That is, the CORESET setting and the search space setting of SCell and PCell are set independently of each other. Accordingly, the base station can transmit the NR PDCCH according to each characteristic of the PCell and the SCell. For example, as described with reference to FIG. 13, in the PCell where LTE and 5G coexist, the degree of freedom of NR PDCCH mapping may be lower than that of the SCell. In this case, the NR PDCCH transmission can be tailored to the characteristics of each cell through method 3.

The base station may determine which method among the method 1, method 2, and method 3 to be applied and inform the terminal.

21 is a diagram illustrating an apparatus for transmitting and receiving a terminal in a wireless communication system according to an embodiment of the present disclosure. For convenience of description, illustration and description of devices not directly related to the present disclosure may be omitted.

Referring to FIG. 21 , the terminal includes a transmitter 2104 including an uplink transmission processing block 2101 , a multiplexer 2102 , and a transmission RF block 2103 , a downlink reception processing block 2105 , and a demultiplexer 2106 . ), it may be composed of a receiving unit 2108 and a control unit 2109 composed of a receiving RF block 2107 . As described above, the control unit 2109 controls each of the constituent blocks of the receiving unit 2108 for reception of a data channel or a control channel transmitted by the base station and each of the constituent blocks of the transmitting unit 2104 for transmitting an uplink signal. can do.

The uplink transmission processing block 2101 in the transmitter 2104 of the terminal may generate a signal to be transmitted by performing a process such as channel coding and modulation. The signal generated in the uplink transmission processing block 2101 may be multiplexed with other uplink signals by the multiplexer 2102 , and then signal-processed in the transmission RF block 2103 and then transmitted to the base station.

The reception unit 2108 of the terminal demultiplexes the signal received from the base station and distributes it to each downlink reception processing block. The downlink reception processing block 2105 may obtain control information or data transmitted from the base station by performing processes such as demodulation and channel decoding on the downlink signal of the base station. The terminal receiver 2108 may support the operation of the controller 2109 by applying the output result of the downlink reception processing block to the controller 2109 .

22 is a block diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure.

As shown in FIG. 22 , the terminal of the present disclosure may include a processor 2230 , a transceiver 2210 , and a memory 2220 . However, the components of the terminal are not limited to the above-described example. For example, the terminal may include more or fewer components than the aforementioned components. In addition, the processor 2230 , the transceiver 2210 , and the memory 2220 may be implemented in the form of a single chip. According to an embodiment, the transceiver 2210 of FIG. 22 may include the transmitter 2104 and the receiver 2108 of FIG. 21 . Also, the processor 2230 of FIG. 22 may include the controller 2109 of FIG. 21 .

According to an embodiment, the processor 2230 may control a series of processes in which the terminal may operate according to the above-described embodiment of the present disclosure. For example, in a wireless communication system to which a carrier bundle according to an embodiment of the present disclosure is applied, the components of the terminal may be controlled to perform the method of transmitting and receiving the terminal. There may be one or a plurality of processors 2230, and the processor 2230 executes a program stored in the memory 2220 to perform a transmission/reception operation of a terminal in a wireless communication system to which the carrier bundle of the present disclosure is applied. .

The transceiver 2210 may transmit/receive a signal to/from the base station. A signal transmitted and received with the base station may include control information and data. The transceiver 2210 may include an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting a received signal. However, the transceiver 2210 is only an embodiment, and the components of the transceiver 2210 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 2210 may receive a signal through a wireless channel, output it to the processor 2230 , and transmit a signal output from the processor 2230 through a wireless channel.

According to an embodiment, the memory 2220 may store programs and data necessary for the operation of the terminal. Also, the memory 2220 may store control information or data included in a signal transmitted and received by the terminal. The memory 2220 may be configured as a storage medium or a combination of storage media, such as ROM, RAM, hard disk, CD-ROM, and DVD. In addition, the memory 2220 may be plural. According to an embodiment, the memory 2220 stores a program for performing a transmission/reception operation of a terminal in a wireless communication system to which a carrier bundle, which is the above-described embodiments of the present disclosure, is applied. can

23 is a block diagram illustrating a configuration of a base station according to an embodiment of the present disclosure.

As shown in FIG. 23 , the base station of the present disclosure may include a processor 2330 , a transceiver 2310 , and a memory 2320 . However, the components of the base station are not limited to the above-described example. For example, the base station may include more or fewer components than the aforementioned components. In addition, the processor 2330 , the transceiver 2310 , and the memory 2320 may be implemented in the form of a single chip.

The processor 2330 may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure. For example, components of a base station may be controlled to perform a method for scheduling a terminal in a mobile communication system supporting a carrier bundle according to an embodiment of the present disclosure. The processor 2330 may be one or plural, and the processor 2330 executes a program stored in the memory 2320 to perform a method of scheduling a terminal in a mobile communication system supporting the carrier bundle of the present disclosure described above. have.

The transceiver 2310 may transmit/receive a signal to/from the terminal. A signal transmitted and received with the terminal may include control information and data. The transceiver 2310 may include an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting a received signal. However, the transceiver 2310 is only an embodiment, and components of the transceiver 2310 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 2310 may receive a signal through a wireless channel, output it to the processor 2330 , and transmit a signal output from the processor 2330 through a wireless channel.

According to an embodiment, the memory 2320 may store programs and data necessary for the operation of the base station. Also, the memory 2320 may store control information or data included in a signal transmitted and received by the base station. The memory 2320 may be configured as a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Also, there may be a plurality of memories 2320 . According to an embodiment, the memory 2320 may store a program for performing a method of scheduling a terminal in a mobile communication system supporting carrier bundles, which are embodiments of the present disclosure described above.

Methods according to the embodiments described in the claims of the present disclosure or the description of the invention may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium or computer program product storing one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium or computer program product are configured for execution by one or more processors in an electronic device (device). One or more programs include instructions for causing an electronic device to execute methods according to embodiments described in a claim or specification of the present disclosure.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable ROM (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or any other form of It may be stored in an optical storage device or a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all thereof. In addition, each configuration memory may be included in plurality.

In addition, the program accesses through a communication network composed of a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. It may be stored in an attachable storage device that can be accessed. Such a storage device may be connected to a device implementing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may be connected to the device implementing the embodiment of the present disclosure.

In the present disclosure, the term "computer program product" or "computer readable medium" refers to a medium such as a memory, a hard disk installed in a hard disk drive, and a signal as a whole. used for These "computer program products" or "computer-readable recording medium" are means provided for a method of transmitting and receiving a terminal in a wireless communication system to which a carrier wave bundle according to the present disclosure is applied.

In the specific embodiments of the present disclosure described above, elements included in the present disclosure are expressed in the singular or plural according to the specific embodiments presented. However, the singular or plural expression is appropriately selected for the context presented for convenience of description, and the present disclosure is not limited to the singular or plural component, and even if the component is expressed in plural, it is composed of a singular or singular. Even an expressed component may be composed of a plurality of components.

On the other hand, in the present specification and drawings, a preferred embodiment of the present disclosure has been disclosed, and although specific terms are used, these are only used in a general sense to easily explain the technical content of the present disclosure and help the understanding of the present disclosure, It is not intended to limit the scope of the disclosure. For example, although the present disclosure is based on a combination scenario of different systems of LTE and 5G, it may be generalized and applied to a carrier bundling operation in the same system (eg, 5G). Alternatively, it may be applied to a scenario of combining 5G and 6G systems to be introduced in the future. It will be apparent to those of ordinary skill in the art to which the present disclosure pertains that other modifications based on the technical spirit of the present disclosure may be implemented in addition to the embodiments disclosed herein. In addition, each of the above embodiments may be operated in combination with each other as needed.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should be defined by the claims described below as well as the claims and equivalents.

Claims (10)

A method by a terminal in a wireless communication system, comprising:
Receiving, from the base station, information related to setting of cross-carrier scheduling of a secondary cell (SCell);
receiving a physical downlink control channel (PDCCH) by monitoring a search space of the SCell, wherein the PDCCH includes a carrier indicator field; and
and identifying whether the PDCCH is for the cross-carrier scheduling or for self-scheduling based on the carrier indicator field.
According to claim 1,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to the same value as the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell), and the SCell is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of .
According to claim 1,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to a value different from the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell), and the SCell is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of .
According to claim 1,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of the SCell, and the primary cell ( The PDCCH transmitted through the PCell) does not include a carrier indicator field.
According to claim 1,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is the same as or different from the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell). The PDCCH for the self-scheduling of the SCell does not include a carrier indicator field.
A method by a base station in a wireless communication system, comprising:
transmitting, to the terminal, information related to the configuration of cross-carrier scheduling of a secondary cell (SCell); and
Transmitting, to the terminal, a physical downlink control channel (PDCCH) through the SCell,
The carrier indicator field is used to identify whether the PDCCH is for the cross-carrier scheduling or for self-scheduling.
7. The method of claim 6,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to the same value as the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell), and the SCell is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of .
7. The method of claim 6,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to a value different from the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell), and the SCell is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of .
7. The method of claim 6,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is set to a value different from the value of the carrier indicator field of the PDCCH for the self-scheduling of the SCell, and the primary cell ( The PDCCH transmitted through the PCell) does not include a carrier indicator field.
7. The method of claim 6,
When the PDCCH is for the cross-carrier scheduling, the value of the carrier indicator field of the PDCCH is the same as or different from the value of the carrier indicator field of the PDCCH transmitted through the primary cell (PCell). The PDCCH for the self-scheduling of the SCell does not include a carrier indicator field.

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